JPH02215958A - Cold start fuel supply for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent any waste consumption of a battery as well as to make a device compact in size by setting up a solenoid on-off valve in the point midway between a combustion chamber in a carburetor and an intake passage, and closing this solenoid on-off valve by means of an output signal of a flywheel magnet. CONSTITUTION:A normally-cloded type solenoid on-off valve 61 is set up in the point midway between a combustion chamber 26 in a carburetor and an intake passage 9. This solenoid on-off valve 61 is closed by an output signal of a primary coil 30a of a fly wheel magnet 30, while a starter motor 29 is stopped. Simultaneously with engine starting, this starter motor comes to a stop. Thus, waste consumption of a battery can be prevented, and a device itself can be miniaturized as well.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a system in which starting fuel is automatically supplied in relation to engine starting conditions, and after the engine is started, the supply of starting fuel is automatically stopped; The present invention relates to a starting fuel supply system for an internal combustion engine in which the starting motor is also stopped at the same time.

[Prior Art] The present applicant has disclosed in Japanese Patent Application No. 63-166473@ that in a small internal combustion engine such as a portable working machine, in order to supply a rich air-fuel mixture to the engine at low temperature start, the ambient concentration is detected by a temperature switch. We are applying for a system that drives an electric fuel pump to supply starting fuel to the intake passage of the carburetor when the ambient temperature is low, but adding a new electric fuel pump and temperature switch would be costly. This is undesirable because it increases the height, increases the size of the device, and increases the weight.

Furthermore, portable working machines cannot be equipped with large-capacity batteries in order to reduce their weight, so if the starting switch is held down by mistake during the starting operation, the battery will be discharged. Portable work machines that are not equipped with a recoil device to reduce weight cannot be started without a charged battery.

The present applicant filed a patent application No. 63-29906@ for a starting device for an internal combustion engine that does not cause erroneous operation. According to this starting device, the engine can be reliably started by the starting motor regardless of the engine or ambient concentration.

However, even with this starter, stopping the starting motor is
Since the user has to make a judgment based on the sound of the engine's operation, the battery may be exhausted by continuing to uselessly press the start switch even though the engine has already reached idling speed.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to provide a system in which starting fuel is automatically supplied to the engine in accordance with the starting conditions of the engine, and the starting motor is stopped at the same time as the engine starts. An object of the present invention is to provide a starting fuel supply device for an internal combustion engine that prevents unnecessary consumption of a battery.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention is such that a normally closed electromagnetic on-off valve is disposed between the fuel chamber of the carburetor and the intake passage, and the flywheel 7-gnet The output signal from the primary coil closes the electromagnetic on-off valve and stops the starter motor.

[Operation] When the starting switch 62 is closed, the relay switch 63a is closed, the starting electric motor 8129 is rotated, and at the same time, the normally closed electromagnetic on-off valve 61 is opened. Immediately after the starting operation, the engine speed is equal to the speed of the starting electric motor 129, and the fuel in the fuel tank 18 is pumped into the metering chamber 26, which serves as a fuel chamber, by the fuel pump 8.
The fuel is supplied to the fuel reservoir chamber 10 of the carburetor 1 via the electromagnetic on-off valve 61. Eventually, the starting fuel in the fuel reservoir chamber 10 is drawn into the intake passage 9, so that the air-fuel mixture is sent to the engine 1131, and the engine 31 is started.

When the engine rotation speed becomes higher than the rotation speed of the starter motor 29, it is detected from the current or voltage of the primary coil 30a of the flywheel magneto 30 that the engine 31 is in an idle rotation state. That is, since the energizing circuit of the relay coil 63 is opened, the starter motor 1129 is stopped, and unnecessary consumption of the battery is avoided. At the same time, the electromagnetic on-off valve 61 closes, and the supply of starting fuel from the metering chamber 26 serving as a fuel chamber to the fuel reservoir chamber 10 is interrupted.

However, since starting fuel remains in the fuel reservoir chamber 10,
The rich air-fuel mixture continues to be supplied to the engine 31 for a while, and the engine 31 is smoothly warmed up.

[Embodiments of the Invention] FIG. 1 is a schematic diagram of a starting fuel supply system for an internal combustion engine equipped with a diaphragm type carburetor. The starting fuel supply device includes a diaphragm-type fuel pump A, a fuel supply mechanism B, and an electromagnetic R closing valve 61 that opens and closes a passage between the fuel supply mechanism B and the fuel reservoir chamber 10 in the main body 4 of the carburetor 1. , solenoid on-off valve 6
1 operation of machine WA31 flywheel magneto 30
Control circuit 37 that controls based on the signal from the next coil 30a
It is equipped with

The carburetor 1 has a cylindrical portion 7 that crosses an intake passage 9 of a carburetor main body 4.
A rotary throttle valve 8 is rotatably and axially movably supported. A throttle valve 8 having a throttle hole 8a has a lever 2 connected to its upper end copper small diameter shaft, and a follower hanging down from the lever 2 has a cam 3 formed in a blue plate 3 that closes a cylindrical part 7.
The engagement is biased by a spring not shown in a. Lever 2
When the opening degree is increased by rotating the valve 8, the throttle valve 8
The rod valve 5 connected to the fuel injection hole 6a is raised, the opening degree of the fuel injection hole 6a is increased, the amount of fuel is increased, and 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 comparator valve 8 , and when the engine 31 is started, the fuel in the fuel reservoir 10 is sucked 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 are divided by the pulsating pressure introduction chamber and the pulsating pressure introduction chamber is connected to the crank chamber of the engine 31. The pump chamber is connected to the fuel tank 18 via a check valve 27 and a passage 55, and is connected to a fuel chamber called a metering chamber 26 of the fuel supply mechanism B via a check valve 24, a passage 15 and an inlet valve 23. Ru. Furthermore, a passage 15a branched from the passage 15
is connected to a fuel tank 18 via a throttle 16.

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 into engagement with the diaphragm 19 by a spring, while the other end is engaged with the inflow valve 2.
3 is biased and engaged to close it. The metering chamber 26 communicates with the fuel injection hole 6a of the fuel pipe 6 via the fuel jet 25. Additionally, the metering room 26 is located in the passage 1.
4. At 17, when the electromagnetic on-off valve 61 is closed, it is communicated with the aforementioned fuel reservoir chamber 10 via the passage 11.

FIG. 2 is a circuit diagram of the IIJI 11 that controls the operation of the electromagnetic on-off valve 61 and the starter motor 29. As shown in the left half of FIG. 2, an ignition circuit unit 32 that drives an ignition plug 40 by a flywheel magnet 30 is connected to a battery 36 via a diode 34. 33 is the spark plug 40
This is a stop switch that short-circuits both terminals of the engine 31 to stop the engine 31. Relay switch 63a for battery 36
Start electric after! 129 and a parallel circuit of the electromagnetic on-off valve 61 are connected.

Relay switch 63 a for battery 36,! A closing relay coil 63, a starting switch 62, and a control circuit 37 are connected. The control circuit 37 performs a switching function based on the current or voltage of the primary coil 30a of the flywheel magnet 30.

As shown in the right half of FIG. 2, the control circuit 37 is configured. 43 to 47, 49 to 51 are resistors, 42 is a Zener diode, 41.54 is a capacitor, 48.52 is a transistor, and 56 is a diode.

Next, the operation of the starting fuel supply system for an internal combustion engine according to the present invention will be explained. When the start switch 62 is closed, II
Since the output transistor 52 of the I control circuit 37 becomes conductive as described later, the relay coil 63 is excited, the relay switch 63a is closed, and the starting motor 29 is rotated.
At the same time, the electromagnetic on-off valve 61 is opened. The flywheel is rotated together with the crankshaft of the engine 31, and the primary coil 30a
An induced current flows through the secondary coil 30b, and a high voltage is applied between both terminals of the spark plug 40 in synchronization with the rotation of the engine 31.

The induced voltage in the primary coil 30a increases in proportion to the engine speed, and when the engine 31 is being driven by the starting motor 29, it is very low as shown by the broken line in FIG. , when it reaches idle rotation, it increases as shown by the solid line in Figure 13.

In FIG. 2, if the voltage of the primary coil 30a is low,
From the primary coil 30a to the diode 56 and the resistor 43.44
．． The current flowing through 45.47 to the base of transistor 48 is very small and transistor 48 is non-conducting. At this time, from the battery 36 to the relay switch 63
a. A large amount of current flows through the resistor 43°49.50 to the base of the transistor 52, making the transistor 52 conductive.
Relay coil 63 is excited and relay switch 63a is closed. The electromagnetic coil of the electromagnetic on-off valve 61 is excited,
As described above, the electromagnetic on-off valve 61 is opened. The current flowing through the resistor 51 is set to be minute.

When the engine 31 is started and 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 becomes conductive. Accordingly, current flows from the battery 36 to the switch 63a.
, resistance 43. '49, the current flows to the negative electrode of the battery 36 via the transistor 48, and the current flowing to the base of the transistor 52 via the resistor 50 is drastically reduced, causing the transistor 52 to become non-conductive. Due to the non-conduction of the transistor 52, the relay coil 6
3 is demagnetized and the relay switch 63a is opened, so
The starter motor 29 is stopped, and at the same time the electromagnetic on-off valve 61 is closed.

As mentioned above, when the engine FII 31 reaches idle rotation, the electromagnetic on-off valve 61 closes, so that the engine 31, such as the ambient temperature,
Starting fuel is supplied to create a rich air-fuel mixture in accordance with the operating conditions, and the engine 31 is started smoothly. Also, since the starting motor 29 stops at the same time as the engine 31 starts,
This prevents the battery 36 from being consumed due to unnecessary rotation of the starting electric motor VlA29.

As shown by the solid line in Fig. 4, when the ambient temperature is low, when the starting electric motor 5li29 is rotated (rotation speed 01), the diaphragm of the fuel pump A (Fig. 1) is caused by the pulsating pressure in the crank chamber of the engine 31. 28 is reciprocated up and down, and the fuel in the fuel tank 18 passes through the passage 55 and the check valve 27 to the fuel pump A.
It is sucked into the pump chamber, and the check valve 24, the passage 15,
It is supplied to the metering v28 via the inflow valve 23. The fuel in the metering chamber 26 is supplied through the fuel jet 25 from the fuel nozzle hole 6a to the throttle hole 8a. At the same time, the fuel in the metering chamber 26 is sent to the fuel reservoir chamber 10 via the passage 14, the valve 17, the electromagnetic on-off valve 61, and the passage 11, and the fuel in the fuel reservoir chamber 10 is sucked into the intake passage 9, so that it is concentrated. The air-fuel mixture is sent to the engine 31, and the engine 31 is started.

When the machine 1II 31 reaches a rotation speed close to the idle rotation (rotation speed n2), the starter motor 29 stops and the electromagnetic on-off valve 6
1 is closed, and fuel in the metering chamber 26 is no longer supplied to the fuel reservoir chamber 10. However, for a while, the fuel storage chamber 10
Since the starting fuel remaining in the engine 31 continues to be sent to the intake passage 9, smooth warm-up of the engine 31 is maintained.

Even if the engine 31 reaches idle rotation, the electromagnetic on-off valve 6
1 is not closed, the fuel in the metering chamber 26 will continue to be supplied to the full fuel chamber 10, so that a rich mixture will still be supplied to the engine 31.

In this case, as shown by the broken line in FIG. 4, the engine 31 becomes malfunctioning and eventually stops. In FIG. 4, the reason why it takes some time for the engine 31 to reach idle rotation is because the fuel vaporization is poor due to the low temperatures of the engine and the outside air.

On the other hand, if the ambient temperature around the machine G931 is 1 degree high, or if the engine is restarted after stopping even at a low temperature, when the starting electric motor 1m29 is rotated, the engine 31 is started instantly, and when it reaches idle rotation, the starting electric motor 29 stops. During this time, the fuel in the metering chamber 26 is supplied to the fuel reservoir chamber 10 via the electromagnetic on-off valve 61, but as soon as the engine 31 reaches idle speed, the electromagnetic on-off valve 61 closes, as shown by the solid line in FIG. In addition, the idle rotation of 111I31 is maintained smoothly.

If the electromagnetic on-off valve 61 remains open, as shown by the broken line in FIG. 5, even if the engine 31 reaches idling speed, a rich air-fuel mixture will continue to be supplied to the engine 31, causing the engine 31 to malfunction. comes and eventually stops.

In addition, in the above-mentioned embodiment, the electromagnetic on-off valve is controlled by the voltage or current change of the primary coil of the flywheel magneto, but the electromagnetic on-off valve is controlled by the number of pulses of the voltage of the primary coil instead of the voltage. be able to.

The present invention also applies to the flywheel mask shown in FIG. −
The transfer point 3o is not limited to the breaker point method, but also the TCI method (tranSi3jer control;
ijton) can also be applied.

Figure 6 shows the CD1 system (Capacitvdischar).
FIG. 1 is an electric circuit diagram of a starting fuel supply device applied to the GE1GN1TION. In this embodiment, the voltage or current from the generator coil 64, which is loaded with magnetic force by the contact and separation of the permanent magnet attached to the flywheel, is used as a signal to 111.
0 circuit 37 performs a switching action. As is known,
In the CD1 method, the current of the generator coil 64 is stored in a capacitor, and when the thyristor is turned on, the current of the generator coil 64 is stored in 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 includes a normally closed electromagnetic on-off valve disposed between the fuel chamber of the carburetor and the intake passage, and the electromagnetic on-off valve is operated by the output signal of the primary coil of the flywheel magneto. The opening/closing valve opens the opening/closing valve and stops the starting motor, so when the engine is rotated by the starting motor, the fuel in the fuel chamber is supplied to the fuel reservoir chamber via the electromagnetic opening/closing valve, and the intake air is discharged from the fuel reservoir chamber. Starting fuel is supplied to the passage and a rich mixture is supplied to the engine, but as soon as the engine is started, the electromagnetic on-off valve is opened, so the supply of starting fuel from the fuel chamber to the fuel reservoir chamber is interrupted. , smooth engine startup and subsequent idle rotation are maintained. In particular, during high-temperature startup, the engine is started immediately after cranking by the starter motor, so that almost no starting fuel is supplied that interferes with smooth idling of the engine.

According to the present invention, as described above, starting fuel is supplied to the engine in just the right amount and under the necessary starting fuel conditions without using a temperature switch, so the engine can be started smoothly and the configuration can be simplified. , cost is saved.

According to the present invention, since the starting motor stops at the same time as the engine starts, the operation is easier than in the conventional system in which the driver stops the starting motor (by releasing the starting switch) based on the sound of the sn running. , unnecessary consumption of the battery is avoided. In other words, the battery installed in the portable working machine can function satisfactorily even if it has a small capacity, and the weight can be reduced, and the battery charging device can also be downsized.

According to the present invention, as a starting fuel supply device for an internal combustion engine,
Since all the components are centrally arranged around the periphery of the vaporizer, the device can be made compact.

[Brief explanation of the drawing]

Fig. 1 is a side view cross-sectional 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 same device, and Fig. 3 is a rotation of the primary coil of a flywheel magneto. FIG. 4.5 is a characteristic diagram of engine starting characteristics, and FIG. 6 is an electric circuit diagram of a starting fuel supply system for an internal combustion engine according to a partially modified embodiment of the present invention.

Claims (1)

[Claims] A normally closed electromagnetic on-off valve is disposed between the fuel chamber of the carburetor and the intake passage, and the electromagnetic on-off valve is closed by the output signal of the primary coil of the flywheel magnet, and the starting motor is stopped. A starting fuel supply device for an internal combustion engine, characterized in that: