JPH03246358A - Starting fuel feeding device for carburetter - Google Patents

Abstract

PURPOSE:To smoothly start an engine without starting motor by providing a manual pump in a passage to connect a fuel chamber of carburetter with a fuel tank, in an engine in which the fuel chamber of the carburetter and a suction passage are connected by a starting fuel feeding passage furnishing an electromagnetic switching valve. CONSTITUTION:A starting fuel feeding device of an internal combustion engine for a portable working machine furnishes the main body 4 of a carburetter 1 with a diaphragm type fuel pump A, a fuel feeding mechanism B, and an electromagnetic switching valve C to open and close starting fuel feeding passages 11 and 14 between the fuel feeding mechanism B and a suction air passage 9, and the electromagnetic switching valve C is controlled by a control circuit 37 depending on the signal of the primary coil 30a of a flywheel magnet 30 of an engine 31. In this case, the upstream part from the throttle 17 of the fuel feeding passage 14 is communicated to a fuel tank 18 through a pipe 14a, a check valve 39a, a manual pump 39, a check valve 39b, and a pipe 14a. The manual pump 19 is composed to push out the fuel in a container by manually squeezing the container made of a rubber and the like, which can be expanded and contracted.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention is a mobile device! ! The present invention relates to a starting device for an aircraft internal combustion engine, and in particular to a starting fuel supply device for a carburetor.

(Prior Art) When the fuel tank runs out of fuel, of course, and when the engine is not used for a long period of time, the fuel in the fuel chamber of the carburetor or the fuel pipe evaporates and disappears.

In preparation for such a case, the present applicant has filed Japanese Patent Application No. 63299.
No. 026@ filed an application for a starting device for an internal combustion engine for a portable working machine equipped with a starting motor. According to this starting fuel supply device, start! At the same time as the engine Dt/s is driven, starting fuel is supplied to the carburetor depending on starting conditions such as ambient temperature, and smooth and reliable starting of the engine is obtained.

[Problems to be Solved by the Invention] As described above, in an internal combustion engine equipped with a starting motor, due to the suction action caused by the rotation of the engine, fuel in the fuel tank passes through the carburetor and flows into the intake passage in a short period of time. \Supplied. However, in the case of an engine without a starting motor, 1.2
If the engine is rotated intermittently due to excessive coil operation, fuel intake will be poor and the engine will have difficulty starting.

In view of the above-mentioned problems, an object of the present invention is to provide starting fuel for a carburetor, which allows starting fuel to be supplied in accordance with starting conditions at the same time as recoil operation, and to smoothly start the engine even in an internal combustion engine without a starting motor. The purpose is to provide a supply device.

[Means for Solving the Problem 1] In order to achieve the above object, the configuration of the present invention is such that the electromagnetic on-off valve provided in the starting fuel supply passage connecting the fuel chamber of the carburetor and the intake passage is connected to the flywheel magnet of the internal combustion engine. In a carburetor starting fuel supply system that is activated by the output signal of the primary coil, a passage connecting the fuel chamber and the fuel tank of the carburetor is
It is equipped with a manual pump to allow fuel to flow from the fuel chamber to the fuel tank.

[Function] Before starting the engine, after filling the fuel chamber of the fuel tank and the starting fuel supply passage of the carburetor with the fuel in the fuel tank using the manual pump, when the recoil is operated, the electromagnetic on-off valve is opened and the starting fuel is supplied to the fuel in the carburetor. Since the air is drawn from the chamber into the intake passage, a rich air-fuel mixture is supplied to the engine and the engine is started smoothly.

Embodiment 1 of the Invention FIG. 1 is a schematic configuration diagram of a starting fuel supply system according to an embodiment of the present invention in the case of a diaphragm type carburetor. The starting fuel supply position 8 includes a diaphragm-type fuel pump A, a fuel supply mechanism B, and an electromagnetic on-off valve that opens and closes a starting fuel supply passage between the fuel supply mechanism B and the intake passage 9 in the main body 4 of the carburetor 1. C, and a control circuit 37 that controls the operation of the electromagnetic on-off valve C based on a signal from the primary coil 30a of the flywheel magnet 30 of the engine 31.

In the carburetor 1, a rotary throttle valve 8 is rotatably and axially movably supported by a cylindrical portion 7 that crosses an intake passage 9 of a main body 4. A lever 2 is connected to the upper end side of the throttle valve 8 having a small-diameter shaft portion, and a follower hanging from the lever 2 is connected to a cam 3a formed on a lid 3 that closes a cylindrical portion 7 by a spring (not shown). Forced engagement. When the throttle valve 8 is rotated by the lever 2 to increase its opening, the rod valve 5 connected to the throttle valve 8 rises, the opening of the fuel injection hole 6a of the fuel supply pipe 6 increases, and the amount of fuel increases. Then, the output of the engine 31 is increased.

A fuel reservoir 10 for retaining starting fuel is formed at the bottom of the cylindrical portion 7 , that is, below the throttle valve 8 , and when the three engines are started, the fuel in the fuel reservoir 10 is taken in through the gap between the cylindrical portion 7 and the throttle valve 8 . It is sucked into the passage 9. The fuel reservoir chamber 10 preferably accommodates a porous member such as ceramics.

The fuel pump A has a diaphragm 28 inside the carburetor body 4.
The pulsating pressure introduction chamber and the pump chamber 28a are divided by
The pulsating pressure introduction chamber is connected to the crank chamber of the two-stroke engine 31. The pump chamber 28a is connected to the fuel tank 18 via the check valve 27 and the pipe 55, while the pump chamber 28a is connected to the fuel tank 18 via the check valve 27 and the pipe 55.
, metering chamber 2 of fuel supply mechanism B via inflow valve 23
It is connected to a fuel chamber designated 6.

The fuel supply mechanism B includes a diaphragm 1 inside the carburetor body 4.
A metering chamber 26 and an atmospheric chamber 20 are divided by 9. The lever 21 is supported by a support shaft 22 inside the metering chamber 26 . One end of the lever 21 is biased by a spring against the diaphragm 19, while the other end engages the inlet valve 23 and is biased to close it. The metering chamber 26 is communicated with the fuel injection hole 6a of the fuel supply pipe 6 via the fuel jet 25 and the check valve 38. Further, the metering chamber 26 is communicated with the fuel reservoir chamber 10 in the front j-ho through the passage 14, the valve chamber 17, the valve chamber of the electromagnetic on-off valve C, and the passage 11.

According to the present invention, the upstream portion of the fuel supply passage 14 from the stop 17 includes the passage 14a, the check valve 39a, the manual pump 39,
It is communicated with the fuel tank 18 via the check valve 39b and the pipe 14a. The manual pump 39 has an inflatable container made of rubber or the like, and when the container is crushed by hand, the fuel in the container flows into the check valve 39b.
is pushed open and flows into the fuel tank 18. On the other hand, when the container is released, the restoring force causes the fuel in the metering chamber 26 to flow into the check valve 3.
9a is opened and suctioned into the container.

FIG. 2 is a control circuit diagram for controlling the operation of the electromagnetic on-off valve C. As shown in the left half of FIG. 2, an ignition circuit unit 3 drives an ignition plug 40 by a flywheel magnet 30.
2 is 1! It is connected to a source battery 36 via a diode 34. A stop switch 33 for stopping the engine 31 is connected between both terminals of the spark plug 40.

As shown in the right half of FIG. 2, the control circuit 37 is configured. 33a is a switch interlocking with the stop switch 33;
3 to 47, 49 to 51 are resistors, 42 is a Zener diode, 41.54 is a capacitor, 48.52 is a transistor, and 53.56 is a diode.

Next, the operation of the starting fuel supply system according to the present invention will be explained. First, when the manual pump 39 is repeatedly operated as described above, if there is no fuel in the metering chamber 26,
Air in the metering chamber 26 is sucked into the manual pump 39 through the passage 14, the pipe 14a1 and the check valve 39a, and is discharged into the fuel tank 18 through the check valve 39b and the pipe 14a.

In this way, when the metering chamber 26 becomes negative pressure, the diaphragm 19 is pushed up and the inflow valve 23 is opened. Since the negative pressure in the metering chamber 26 acts on the pump chamber 28a of the fuel pump A through the check valve 24, the fuel in the fuel tank 18 passes through the pipe 55 and pushes open the check valve 27, causing the pump air to open 28a.
The check valve 24, the passage 15, the inflow valve 23
The metering chamber 26 is filled with light. When the manual pump 39 is subsequently operated, the fuel in the metering chamber 26 flows through the passage 14, the check valve 39a, the manual pump 39, and the check valve 39.
b, is returned to the fuel tank 18 via the pipe 14a. At the same time, the air in the passage 14 and the throttle 17 is also discharged to the fuel tank 18 by the manual pump 39, and the passage 14 and the throttle 17 are filled with fuel.

When the engine 31 is recoiled, the flywheel is rotated together with the crankshaft of the engine 31, and an induced current flows through the primary coil 30a of the flywheel magneto 30, causing the engine 3
A high voltage is applied from the secondary coil 30b to both terminals of the spark plug 40 in synchronization with the rotation of the spark plug 40. The induced voltage in the primary coil 30a increases in proportion to the engine speed. Primary coil 3
The induced voltage at 0a is very low when the engine 31 is being cranked, and becomes high when the engine 31 is started and reaches idle speed.

In FIG. 2, if the voltage of the primary coil 30a is low,
Diode 56, resistance 44.45 from primary coil 30a
．． The current flowing through 47 to the base of transistor 48 is very small and transistor 48 is non-conducting. In addition, the switch 33a and the resistor 4 are connected to the power supply battery 36.
3.49.50, a large amount of current flows to the base of the transistor 52, and the transistor 52 becomes conductive. Electricity is supplied from the ml battery 36 to the negative electrode of the power supply battery 36 via the switch 33a and the electromagnetic on-off valve C, and the iIi magnetic on-off valve C is opened. The current flowing through the resistor 51 is set to be minute.

When the electromagnetic on-off valve C is opened in accordance with the recoil operation of the engine 31, the fuel in the metering chamber 26 flows through the passage 14 and the throttle 17.
, the valve chamber of the electromagnetic on-off valve C, the passage 11, and the fuel reservoir chamber 10, and are sucked into the intake passage 9. At the same time, metering room 26
The fuel is sucked into the intake passage 9 from the fuel injection hole 6a of the fuel supply pipe 6 through the fuel jet 25 and the check valve 38. Since these fuels are mixed with intake air to form a rich mixture and supplied to the engine, the engine 31 can be started smoothly.

When the engine 31 is started and reaches idle rotation, the voltage of the primary coil 30a becomes high, the current flowing to the base of the transistor 48 increases, and the transistor 48 becomes conductive. Along with this, from the power supply battery 36 to the switch 33
a, the current flows through the resistor 43, 49 and the transistor 48 to the negative electrode of the power supply battery 36, and the current flowing through the resistor 50 to the base of the transistor 52 is drastically reduced, the transistor 52 becomes non-conductive, and the electromagnetic on-off valve C Since power is no longer applied to the engine, the electromagnetic on-off valve C is closed, and the supply of starting fuel is cut off.

When the engine 31 is started as described above, the diaphragm 28 of the fuel pump A is reciprocated up and down by the pulsating pressure from the crank of the engine 31, and the fuel in the fuel tank 18 is pumped into the pipe 5.
5. The fuel is sucked into the pump chamber 28a of the fuel pump Δ via the check valve 27, and further supplied to the metering chamber 26 via the check valve 24, the passage 15, and the inflow valve 23. The fuel in the metering chamber 26 is supplied to the intake passage 9 from the fuel injection hole 6a of the fuel supply pipe 6 via the fuel jet 25 and the check valve 38.

In the above-mentioned embodiment, the electromagnetic on-off valve C is controlled by the voltage change of the primary coil 30a of the flywheel magnet 30. Control on-off valve C 111j
can be done.

In the embodiment shown in FIG. 3, a manual pump 39 and a pressure accumulator 61 are arranged in the middle of the starting fuel supply passage 14 connecting the metering v26 and the electromagnetic on-off valve C, and the outlet of the pressure accumulator 61 and the fuel tank 18 A pipe 14a having a relief valve 67 is connected between the two.

The pressure accumulator 62 connects the periphery of a diaphragm 65 to the container 61 to partition an atmospheric chamber 64 and a pressure accumulating chamber 66.
The force of the spring 63 housed in the diaphragm 65 presses the diaphragm 65 to pressurize the pressure accumulation chamber 66.

In this embodiment, the manual pump 39 is
When the metering chamber 26 is operated, the air in the metering chamber 26 is removed to the fuel tank 18, the fuel in the fuel tank 18 is filled into the metering chamber 26, and the fuel in the metering chamber 26 is transferred to the passage 1.
4. The pressure accumulator 66 of the pressure accumulator 61 is pressurized and filled through the check valve 39a1, the manual pump 39, and the check valve 39b, and the excess fuel passes through the pipe 14a, pushes open the relief valve 67, and fills the fuel tank 1.
It is discharged to 8.

When the electromagnetic on-off valve C is opened in accordance with the operation of the engine fuel coil, the pressurized starting fuel in the pressure accumulation chamber 66 is ejected into the intake passage 9 through the passage 14, the electromagnetic on-off valve C1 passage 11, and the fuel reservoir chamber 10. A rich mixture is supplied to the engine.

In the embodiment shown in FIG. 4, a manual pump 39A having a check valve 39a and an expandable container made of rubber or the like is connected in the middle of a pipe 55 connecting the fuel tank 18 and the inlet of the fuel pump A. A pipe 15a having a throttle 16 is connected between the outlet of the fuel pump A and the fuel tank 18.

*When the manual pump 39A is operated prior to starting wA, the fuel in the fuel tank 18 is filled into the metering chamber 26 through the fuel pump A, and excess fuel is returned to the fuel tank 18 through the pipe 15a having the throttle 16. .

[Effects of the Invention] As described above, the present invention is characterized in that the electromagnetic on-off valve provided in the starting fuel supply passage connecting the fuel chamber of the carburetor and the intake passage is activated by the output signal of the primary coil of the flywheel magneto of the internal combustion engine. In the starting fuel supply system for a carburetor, a manual pump is provided in the passage connecting the fuel chamber of the carburetor and the fuel tank, or the passage connecting the fuel tank and the inlet of the fuel pump. If the fuel chamber of the carburetor is filled with fuel from the fuel tank using a manual pump, the electromagnetic on-off valve in the starting fuel supply passage opens at the same time as the recoil operation, and the fuel in the fuel chamber is sucked into the intake passage through the electromagnetic on-off valve. As a result, a rich mixture is supplied to the engine.
Even engines without a starting motor can be smoothly started.

According to the present invention, since there is no starter motor and therefore the control circuit and the electromagnetic on-off valve can be driven by a small power source battery, an easy-to-operate, lightweight, and low-cost device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a starting fuel supply device for a carburetor according to a first embodiment of the present invention, FIG. 2 is an electric circuit diagram of the starting fuel supply device, and FIG. ．． FIG. 7 is a configuration diagram of a starting fuel supply device according to a third embodiment. A: Fuel pump C: Solenoid on-off valve 9: Intake passage 11.
14: Starting fuel supply passage 18: Fuel tank 26: Metering chamber 30: Flywheel magneto 30a
: Primary coil-39, 39A: Manual pump

Claims (2)

[Claims] (1) In a starting fuel supply system for a carburetor in which an electromagnetic on-off valve provided in a starting fuel supply passage connecting the fuel chamber of the carburetor and an intake passage is activated by an output signal from the primary coil of a flywheel magneto of an internal combustion engine. A starting fuel supply device for a carburetor, characterized in that a manual pump is provided in a passage connecting the fuel chamber and the fuel tank of the carburetor so that fuel flows from the fuel chamber to the fuel tank. (2) In a starting fuel supply system for a carburetor in which the electromagnetic on-off valve provided in the starting fuel supply passage connecting the fuel chamber of the carburetor and the intake passage is activated by the output signal of the primary coil of the flywheel magneto of the internal combustion engine. A starting fuel supply device for a carburetor, characterized in that a manual pump is provided in a passage connecting a fuel tank and an inlet of a fuel pump, and a passage having a restriction is provided between an outlet of a fuel pump and a fuel tank.