JP2002339805A - Automatic choke mechanism of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic choke mechanism of an internal combustion engine or opening and closing a solenoid opening/closing valve arranged in a starting air-fuel mixture passage by electric power from a flywheel magnet. SOLUTION: Provided is the solenoid opening/closing valve 11 for communicating and cutting off a fuel inlet 16 and an air inlet 18 with and from the air-fuel mixture passage 19. The air-fuel mixture passage 19 is connected to a starting air-fuel mixture nozzle port 20 opening in a downstream side part of a throttle valve 5 of an intake air passage 3 of a carburetor. The solenoid opening/closing valve 11 closing at current-carrying time is connected to a terminal of a coil 27 constituting a flywheel magnet mechanism 21 via a temperature sensing switch 29 closing when an ambient temperature of the engine exceeds a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting fuel supply mechanism for supplying a rich air-fuel mixture from a fuel system different from a normal fuel system at the time of a cold start of an internal combustion engine, that is, an auto-choke mechanism.

[0002]

2. Description of the Related Art A conventional auto yoke mechanism opens and closes a starting fuel passage with a thermowax or the like.
In order to operate the thermowax, it must be heated with a predetermined amount of heat.If a heater is provided to obtain the predetermined amount of heat, a power battery for heating the thermowax must be installed, and the auxiliary equipment is large. Become something. Also,
The thermowax has a problem in that the operation thereof is slow, an unnecessarily rich air-fuel mixture is supplied for a long time after the engine is started, and the amount of unburned gas emitted is increased.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an auto-choke mechanism for an internal combustion engine in which an electromagnetic on-off valve provided in a starting air-fuel mixture passage is opened and closed by electric power from a flywheel magneto. Is to provide.

[0004]

In order to solve the above-mentioned problems, the present invention comprises an electromagnetic valve for opening and closing a fuel inlet and an air inlet to and from an air-fuel mixture outlet. The solenoid-operated on-off valve, which is connected to a starting air-fuel mixture injection hole opened at a portion downstream of the throttle valve of the intake path and which constitutes a flywheel magneto, is connected to a terminal that closes when energized.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in an auto-yoke mechanism for an intake passage of an internal combustion engine using gasoline as fuel, electric power obtained by operating the engine is used as a power supply for an electromagnetic on-off valve for supplying and stopping fuel for starting. The solenoid on-off valve opens and closes the fuel passage and the air passage at the same time, improves responsiveness, and simplifies the configuration. The power for driving the solenoid on-off valve is
The power is supplied from the coil facing the magnet attached to the flywheel, eliminating the need for a power battery. The auto yoke mechanism operates directly depending on the engine speed and the ambient temperature.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an auto-chioke mechanism for an internal combustion engine according to the present invention is provided with an intake passage 3 of a carburetor 2 rather than a throttle valve 5 supported by a shaft 4 in order to improve the cold start of the engine. A starting gas mixture injection hole 20 is provided on the downstream side, and the air from the air inlet 28 of the electromagnetic on-off valve 21 and the fuel from the fuel inlet 17 are mixed and supplied to the gas mixture injection hole 20.

The electromagnetic opening / closing valve 21 accommodates the electromagnetic coil 7 inside the cylindrical yoke 8 and fits the plunger 6 made of a magnetic material into the sleeve 6a that supports the electromagnetic coil 7 to constitute a drive unit. A main body 10 is connected to a lower end of the yoke 8 with a gasket 10 interposed therebetween, and a through hole 1 penetrating the main body 10 is provided.
The end of the plunger 10 is inserted into a cylindrical valve chamber 15 orthogonal to 4. An air inlet 18 is connected to the right end of the through hole 14, and an air / fuel mixture outlet at the left end of the through hole 14 is connected to a starting air / fuel mixture injection hole 20 via a passage 19. When the electromagnetic coil 7 is not energized, the plunger 6 is pushed up by the force of the spring 13 interposed between the recess 12 of the main body 10 and the flange 6b connected to the plunger 6, and the through hole 14 is opened. The lower end of the valve chamber 15 is connected to a fuel pipe 17 via a fuel inlet 16. The electromagnetic on-off valve 11 is configured to close the through hole 14 when energized after the warm-up is completed.

As shown in FIG. 2, the terminals of the coil 27 constituting the flywheel magneto 21 are connected to the temperature-sensitive switch 2.
9 and connected to the electromagnetic coil 7. Temperature-sensitive switch 29
Closes when the engine wall or ambient temperature exceeds a predetermined value. That is, the temperature-sensitive switch 29 is disposed at a temperature where the temperature is closed when the engine can be stably operated after the engine is warmed up. The flywheel magneto mechanism 21 supports a permanent magnet 24 and a pair of magnetic pole pieces 25 and 26 connected to circumferential ends of the permanent magnet 24 on a peripheral portion of a flywheel 23 connected to a crankshaft 22 of the engine. On the other hand, the coil 27 is wound around the fixed core 28, and when the magnetic pole pieces 25, 26 are separated from and attached to the fixed core 28 with the rotation of the flywheel 23, electric power is generated at the terminals of the coil 27.

When the engine is stopped, the solenoid on-off valve 11 is open. Since the amount of power generated by the coil 27 cannot be sufficiently obtained at the rotation speed of the crankshaft 22 at the time of starting the engine, the electromagnetic on-off valve 11 does not operate and remains open. When the engine is started, the air from the air inlet 18 of the electromagnetic on-off valve 21 and the fuel from the fuel inlet 16 are mixed in the through hole 14 by the negative pressure of the intake air in the intake passage 3, and mixed through the passage 19 for starting. It is sucked into the air injection hole 20. In this way, the rich mixture is supplied to the engine, so that the engine is started smoothly.

When the engine starts and rises to the idling speed, the coil 27 generates enough electric power to operate the solenoid on-off valve 11 sufficiently. When the temperature around the engine increases and the temperature-sensitive switch 29 closes, power is supplied to the electromagnetic coil 7 and the electromagnetic on-off valve 11 closes instantaneously. When the electromagnetic on-off valve 11 is closed, the supply of the rich mixture is cut off, so that the stable idle operation is continued thereafter.

[0011]

As described above, the present invention is provided with an electromagnetic on-off valve for communicating and shutting off the fuel inlet and the air inlet with the air-fuel mixture outlet,
The air-fuel mixture outlet is connected to a starting air-fuel mixture injection hole opened at a portion downstream of the throttle valve in the intake path of the carburetor, and the terminal of a coil constituting a flywheel magneto is connected to the electromagnetic on-off valve that closes when energized. A starting / closing valve having an electromagnetic opening / closing valve for communicating / cutting off a fuel inlet and an air inlet to / from an air-fuel mixture outlet, wherein the air-fuel mixture outlet is opened to a downstream side of a throttle valve of an intake passage of a carburetor. The terminal of the coil 27 connected to the air injection hole and constituting the flywheel magneto 21 is
When the ambient temperature of the engine exceeds a predetermined value, it is connected to the solenoid on-off valve that closes when energized via a temperature-sensitive switch that closes when the power is turned on.This eliminates the need for batteries required in the conventional auto-choke yoke mechanism. Lighter weight and lower maintenance costs.

Since the electromagnetic on-off valve and the temperature-sensitive switch are used, the responsiveness of the auto-choke yoke mechanism becomes quick, which also helps to shorten the warm-up time.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of an auto-choke mechanism of an internal combustion engine.

FIG. 2 is a front view showing a flywheel magneto mechanism for supplying power to an auto-choke mechanism of the internal combustion engine.

[Explanation of symbols]

2: Vaporizer 3: Inlet path 4: Shaft 5: Throttle valve 6: Plunger 6a: Sleeve 7: Electromagnetic coil 6b: Electromagnetic coil 8: Yoke 9: Gasket 10: Main body
11: solenoid on-off valve 12: hollow 13: spring 14:
Through hole 15: Valve chamber 16: Fuel inlet 17: Fuel pipe 18: Air inlet 1
9: Mixture mixture passage 20: Starting mixture mixture injection hole 21: Generator 22: Crankshaft 23: Flywheel 24: Permanent magnet 25: Magnetic pole piece 26: Magnetic pole piece 27: Coil
28: Fixed iron core 29: Temperature-sensitive switch

Claims (2)

[Claims] A fuel inlet and an air inlet communicate with an air-fuel mixture outlet.
An electromagnetic opening / closing valve for shutting off the air-fuel mixture is connected to a starting air-fuel mixture injection hole opened at a portion downstream of the throttle valve in the intake path of the carburetor, and a terminal of a coil constituting a flywheel magneto is energized. An auto-choke mechanism for an internal combustion engine, wherein the electromagnetic on-off valve is closed. 2. The internal combustion engine according to claim 1, wherein the solenoid on-off valve is connected to a terminal of a coil constituting the flywheel magneto via a temperature-sensitive switch that closes when an ambient temperature of the engine exceeds a predetermined value. Auto chi-yoke mechanism.