JP2780036B2 - Starting fuel supply device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides that starting fuel is automatically supplied in relation to starting conditions of an engine, and after starting of the engine, the supply of starting fuel is automatically stopped. The present invention relates to a starting fuel supply device for an internal combustion engine in which a starting motor is stopped at the same time.

[Prior Art] The applicant of the present invention disclosed in Japanese Patent Application No. 63-166473, in a small internal combustion engine such as a portable work machine, in order to supply a rich air-fuel mixture to the engine at a low temperature start, the ambient temperature was detected by a temperature switch, An application has been filed for driving an electric fuel pump to supply starting fuel to the intake passage of a carburetor when the ambient temperature is low, but adding an electric fuel pump and a temperature switch is costly. However, it is not preferable in that the size of the apparatus becomes large and the weight increases.

In addition, since the portable work machine cannot carry a large-capacity battery because of its weight reduction, the battery is discharged when the start switch is erroneously operated and the start switch is kept pressed.
A portable work machine not equipped with a recoil device for weight reduction cannot start without a charged battery.

The present applicant has filed an application for a starting device for an internal combustion engine which does not cause a malfunction according to Japanese Patent Application No. 63-29906. According to this starting device, the engine can be reliably started by the starting motor regardless of the engine and the ambient temperature. However, even with this starting device, the user must stop the starting motor based on the operating noise of the engine, so the engine has already reached idle speed and the start switch is kept being pushed wastefully. And exhaust the battery.

[Problems to be Solved by the Invention] In view of the above-described problems, an object of the present invention is to automatically supply a starting fuel to an engine according to a starting condition during a starting operation of the engine, and to start the engine when the engine starts. An object of the present invention is to provide a starting fuel supply device for an internal combustion engine, in which fuel supply is stopped and a starting motor is stopped at the same time to prevent useless consumption of a battery.

[Means for Solving the Problems] To achieve the above object, the configuration of the present invention includes a flywheel magnet, and the starting fuel is supplied from the fuel chamber of the carburetor to the intake passage via a normally closed electromagnetic on-off valve. In the internal combustion engine, the transistor switching is made conductive when the engine rotation is equal to or lower than the idle rotation speed and becomes non-conductive when the engine rotation is higher than the idle rotation speed by the output signal of the primary coil of the flywheel magneto. A circuit and a relay coil were connected in series to a power supply, a relay switch closed when the relay coil was excited and the solenoid on-off valve were connected in series with the power supply, and a starting motor was connected in parallel with the solenoid on-off valve. It is characterized by the following.

[Operation] When the start switch is closed, the relay switch is closed and the start motor rotates, and at the same time, the normally closed solenoid on-off valve is opened. The engine speed immediately after the start operation is equal to the speed of the starter motor, and the fuel in the fuel tank is supplied by the fuel pump to the fuel reservoir near the intake passage of the carburetor via the metering chamber as the fuel chamber and the solenoid on-off valve. You. Eventually, the starting fuel in the fuel reservoir is sucked into the intake passage, so that a rich air-fuel mixture is sent to the engine, and the engine starts smoothly.

When the engine speed becomes higher than the starting motor speed,
It is detected from the current or voltage of the primary coil of the flywheel magnet that the engine is in an idle rotation state. That is, since the relay switch is opened, the starting motor is stopped, and wasteful consumption of the battery is avoided. at the same time,
The electromagnetic on-off valve is closed, and the supply of the starting fuel from the metering chamber as the fuel chamber to the fuel storage chamber is interrupted. However, since the starting fuel remains in the fuel reservoir, a rich mixture is continuously supplied to the engine for a while, and the warm-up operation of the engine can be smoothly performed.

Embodiment of the Invention FIG. 1 is a schematic configuration diagram of a starting fuel supply device for an internal combustion engine provided with a diaphragm type carburetor. The starting fuel supply device is provided with a diaphragm type fuel pump A on the main body 4 of the carburetor 1.
An electromagnetic on-off valve 61 for opening and closing the passage between the fuel supply mechanism B, the fuel supply chamber B and the fuel storage chamber 10, and controlling the operation of the electromagnetic on-off valve 61 by the primary coil 30 of the flywheel magnet 30 of the engine 31.
and a control circuit 37 for controlling based on the signal a.

The carburetor 1 is supported by a cylindrical portion 7 traversing an intake passage 9 of the carburetor body 4 so that a rotary type throttle valve 8 is rotatable and axially movable. A throttle valve 8 having a throttle hole 8a has a lever 2 coupled to a small-diameter shaft portion on the upper end side, and a follower hanging down from the lever 2 forms a cam 3a formed on a lid 3 closing a cylindrical portion 7.
Are biased by a spring (not shown). When the throttle valve 8 is rotated by the lever 2 to increase the opening, the rod valve 5 connected to the throttle valve 8 rises, and the opening of the fuel injection hole 6a increases.
The fuel amount increases, and the output of the engine 31 increases.

A fuel reservoir 10 for holding the starting fuel is formed at the bottom of the cylindrical portion 7, that is, below the throttle valve 8, and the fuel in the fuel reservoir 10 at the start of the engine 31 passes through the gap between the cylindrical portion 7 and the throttle valve 8 through the intake passage. 9
Is sucked into. The fuel reservoir 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 introducing chamber and the pump chamber are partitioned by the pulsating pressure introducing chamber, and the pulsating pressure introducing chamber is connected to the engine 31 in the crank chamber. The pump chamber is connected to the fuel tank 18 via the check valve 27 and the passage 55, while the fuel supply mechanism B is connected via the check valve 24, the passage 15 and the inflow valve 23.
Is connected to a fuel chamber called a metering chamber 26. Further, a passage 15 a branched from the passage 15 is connected to a fuel tank 18 via a throttle 16.

The fuel supply mechanism B has a diaphragm inside the carburetor body 4.
The 19 defines a metering chamber 26 and an atmosphere chamber 20. The lever 21 is supported by the support shaft 22 inside the metering chamber 26. One end of lever 21 is diaphragmed by spring
The other end is biased and engaged with the inflow valve 23 to close it. The metering chamber 26 communicates with the fuel injection hole 6a of the fuel pipe 6 via the fuel jet 25. The metering chamber 26 has a passage 14, a throttle 17, an electromagnetic on-off valve 61.
Through the valve chamber and the passage 11 to the fuel reservoir 10 described above.

FIG. 2 is a control circuit diagram for controlling the operations of the solenoid on-off valve 61 and the starting motor 29. As shown in the left half of FIG. 2, an ignition circuit unit 32 for driving an ignition plug 40 by a flywheel magneto 30 is connected to a battery 36 via a diode 34. A stop switch 33 short-circuits both terminals of the spark plug 40 to stop the engine 31. The starting motor 29 and the solenoid on-off valve 6 are connected to the battery 36 via the relay switch 63a.
One parallel circuit is connected. Relay coil 6 closing start switch 62 and relay switch 63a against battery 36
3. The control circuit 37 is connected. The control circuit 37 performs a switching action of exciting and demagnetizing the relay coil 63 by the current or voltage of the primary coil 30a of the flywheel magneto 30.

As shown in the right half of FIG.
47,49-51, zena diode 42, capacitors 41,54
, Transistors 48 and 52, and a diode 56.

Next, the operation of the starting fuel supply device for an internal combustion engine according to the present invention will be described. When the start switch 62 is closed, the output transistor 52 of the control circuit 37 conducts as described later, so that the relay coil 63 is excited and the relay switch 63a is turned on.
Is closed, the starting motor 29 is rotated, and at the same time, the solenoid on-off valve 61 is opened. The flywheel is rotated together with the crankshaft of the engine 31, and the primary coil of the flywheel magneto 30 is rotated.
An induced current flows through 30a, and a high voltage is applied between the two terminals of the ignition plug 40 from the secondary coil 30b in synchronization with the rotation of the engine 31.

The induced voltage of the primary coil 30a of the flywheel magneto 30 increases in proportion to the engine speed, and the engine 31
Is very low as shown by the broken line in FIG. 3, and becomes high as shown by the solid line in FIG. 3 when the engine 31 reaches the idling speed.

In FIG. 2, when the voltage of the primary coil 30a is low,
The current flowing from the primary coil 30a to the base of the transistor 48 via the diode 56 and the resistors 44 and 47 is very small, and the transistor 48 is in a non-conductive state. At this time, battery 36
From the starting switch 62, through the resistors 43, 49, 50, the transistor
Since a large amount of current flows to the base of the transistor 52, the transistor 52 is turned on, the relay coil 63 is excited, and the relay switch 63a is closed. The electromagnetic coil of the electromagnetic on-off valve 61 is excited, and the electromagnetic on-off valve 61 is opened as described above. The current flowing through the resistor 51 is set to be very small.

When the engine 31 reaches idle rotation, the voltage of the primary coil 30a increases, the current flowing to the base of the transistor 48 increases, and the transistor 48 conducts. Accordingly, a current flows from the battery 36 to the negative electrode of the battery 36 via the starting switch 62, the resistors 43 and 49, and the transistor 48, and the current flowing to the base of the transistor 52 via the resistor 50 is drastically reduced. It becomes non-conductive. Due to the non-conduction of the transistor 52, the relay coil 63 is demagnetized even if the start switch 62 is pressed, and the relay switch 63a is opened.
61 is closed.

As described above, during the starting operation of the engine 31, the electromagnetic on-off valve 61 is opened, so that the starting fuel for creating a rich air-fuel mixture corresponding to the operating conditions of the engine 31, such as the ambient temperature, is supplied, and the engine 31 is smoothly operated. Is started. When the engine 31 reaches idle speed,
Since the electromagnetic on-off valve 61 is closed and the starting motor 29 is stopped at the same time, consumption of the battery 36 due to useless rotation of the starting motor 29 is avoided.

As shown by the solid line in FIG. 4, when the ambient temperature is low,
When the starting motor 29 is rotated (rotation speed n1), the diaphragm 28 of the fuel pump A (FIG. 1) reciprocates up and down due to the pulsating pressure of the crank chamber of the engine 31, and the fuel in the fuel tank 18 passes through the passage 55, The gas is sucked into the pump chamber of the fuel pump A 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 through the fuel jet 25 from the fuel injection hole 6a to the throttle hole 8a. At the same time, the fuel in the metering chamber 26
7, sent to the fuel reservoir 10 via the electromagnetic opening and closing valve 61, the passage 11,
Since the fuel in the fuel storage chamber 10 is sucked into the intake passage 9, a rich air-fuel mixture is sent to the engine 31, and the engine 31 starts smoothly.

When the engine 31 reaches a rotation speed close to the idle rotation (rotation speed n2), the starting motor 29 stops, the electromagnetic on-off valve 61 closes,
The fuel in the metering chamber 26 is no longer supplied to the fuel storage chamber 10. However, since the starting fuel remaining in the fuel storage chamber 10 for a while is continuously sent to the intake passage 9, a smooth engine
31 warm-up operations are maintained.

Even if the engine 31 reaches idle rotation, the solenoid on-off valve 61
Is not closed, the fuel in the metering chamber 26 is continuously supplied to the fuel storage chamber 10, so that the rich air-fuel mixture
Supplied to 31. In this case, the engine 31 malfunctions as shown by the broken line in FIG. 4, and eventually stops. In FIG. 4, the reason why it takes some time until the engine 31 reaches the idling speed is that the temperature of the engine and the outside air leads to poor fuel vaporization.

On the other hand, when the ambient temperature of the engine 31 is high, or when the engine 31 is restarted after stopping even at a low temperature, the engine 31 starts instantly when the starter motor 29 is rotated, and starts when the engine 31 reaches idle rotation. Stops. During this time, the fuel in the metering chamber 26 is supplied to the fuel storage chamber 10 via the electromagnetic opening / closing valve 61, but the electromagnetic opening / closing valve 61 closes immediately when the engine 31 reaches the idling speed, as shown by the solid line in FIG. Institution 31
Idle rotation is maintained smoothly.

If the solenoid on-off valve 61 is kept open, as shown by the broken line in FIG.
Since a rich mixture is continuously supplied to the engine 31, the engine 31
Got sick and eventually stopped.

In the above embodiment, the flywheel magneto 1
Although the electromagnetic on-off valve is opened and closed by a change in the voltage or current of the secondary coil, the electromagnetic on-off valve can be opened and closed by the number of pulses of the voltage of the primary coil instead of the voltage.

The present invention also relates to a flywheel magnet shown in FIG.
30 is not limited to the breaker point method, but the TCI method (trans
It can also be applied to ister control ignition).

FIG. 6 is an electric circuit diagram of the starting fuel supply device applied to the CDI method (capacity discharge ignition). In this embodiment, the control circuit 37 performs a switching operation by using a voltage or a current from the power generating coil 64 to which a magnetic force is applied by the separation and connection of the permanent magnet attached to the flywheel as a signal.
As is well known, in the CDI method, the current of the power generation coil 64 is stored in a capacitor, and when the thyristor is turned on, the current is discharged to the primary coil 30a. At this time, a high voltage is generated in the secondary coil 30b.

[Effects of the Invention] As described above, the present invention relates to an internal combustion engine that supplies starting fuel from a fuel chamber of a carburetor to an intake passage through a normally-closed electromagnetic on-off valve, and outputs an output of a primary coil of the flywheel magnet. A transistor switching circuit and a relay coil are connected in series to a power supply when the engine rotation is equal to or less than the idle rotation speed and become non-conductive when the engine rotation exceeds the idle rotation speed by the signal, and the relay coil is connected. Since the relay switch to be closed at the time of excitation and the solenoid on-off valve are connected in series to the power supply, and the starting motor is connected in parallel with the solenoid on-off valve, the following effects are obtained.

When the engine is rotated by the starting motor, the fuel in the fuel chamber is supplied to the fuel reservoir via the solenoid on-off valve, the starting fuel is supplied from the fuel reservoir to the intake passage, and the rich mixture is supplied to the engine. However, as soon as the engine is started, the solenoid on-off valve is closed, so that the supply of the starting fuel from the fuel chamber to the fuel reservoir is interrupted, and the smooth start of the engine and the subsequent idle rotation are maintained. In particular, during high temperature starting, the engine is started immediately after cranking by the starting motor,
Little starting fuel is supplied to prevent smooth idling of the engine.

Even without using a conventional temperature switch, the starting fuel is supplied to the engine without any excess or shortage under the necessary conditions of the starting fuel, so that the engine can be smoothly started and the structure is simplified,
Costs are saved.

Since the starting motor stops at the same time as the engine is started, the operation is easier compared to the conventional method in which the driver stops the starting motor based on the operating sound of the engine (releases the start switch) and the battery is wasted. Is avoided. In other words, even a battery with a small capacity mounted on the portable work machine can function satisfactorily and be lightweight, and the battery charging device can also be miniaturized.

As the starting fuel supply device for the engine, all the components can be centrally arranged around the carburetor, so that the device can be prevented from being enlarged.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a schematic configuration of a starting fuel supply device for an internal combustion engine according to the present invention, FIG. 2 is an electric circuit diagram of the device, and FIG. 3 is a rotation speed of a primary coil of a flywheel magnet. 4 and 5 are engine start characteristic diagrams, and FIG. 6 is an electric circuit diagram of an internal combustion engine start fuel supply engine according to a partially modified embodiment of the present invention. 1: carburetor, 8: throttle valve, 9: intake passage, 10: fuel chamber, 26: fuel chamber, 29: starting motor, 30: flywheel magnet, 30a:
Primary coil, 61: solenoid on-off valve, 62: start switch, 63: relay coil, 63a: relay switch

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shin Suzuki 2-925 Shin Maruko Higashi, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Walbroefeast Co., Ltd. (56) References JP-A-60-216056 (JP, A) ( 58) Field surveyed (Int.Cl. ⁶ , DB name) F02M 1/08 F02M 37/00

Claims (1)

(57) [Claims] 1. An internal combustion engine having a flywheel magnet for supplying starting fuel from a fuel chamber of a carburetor to an intake passage through a normally-closed electromagnetic on-off valve, wherein an output of a primary coil of the flywheel magnet is provided. A transistor switching circuit and a relay coil are connected in series to a power supply when the engine rotation is equal to or less than the idle rotation speed and become non-conductive when the engine rotation exceeds the idle rotation speed by the signal, and the relay coil is connected. A start fuel supply device for a carburetor, characterized in that a relay switch to be closed at the time of excitation and the solenoid on-off valve are connected in series to a power supply, and a starting motor is connected in parallel with the solenoid on-off valve.