JPH11182348A - Auto choke of general purpose gasoline engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically open a choke valve when an engine becomes set engine speed after the engine is started by arranging a switch at a set revolving number location of a lever revolving by interlocking with a governor mechanism and connecting this switch with a suction coil operating the choke valve to its opened side. SOLUTION: When an engine is started, a choke valve 2 of a carbureter is opened by a spring 23 at first. When cranking is performed by a coil starter, negative pressure of a venturi part 48 becomes large, large quantity of fuel is jetted from a main nozzle 5 and an engine is started. When the engine is started and engine speed rises, a governor lever 11 is rotated downward by a governor mechanism. A switch 31 is turned on by coming into contact with an abutting part 32 of the switch 31. As a result, current flows to a suction coil 25, an arm 21 is rotated downward against a spring 23, the choke valve 2 is opened and the engine is operated in air-fuel mixture of normal density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic choke for a general-purpose gasoline engine.

[0002]

2. Description of the Related Art As shown in FIG.
It comprises a mixing chamber 4 and a float chamber 26, both of which are connected by a main nozzle 5. The air passing through the mixing chamber 4 is configured to collide with the fuel discharged from the main nozzle 5, and a throttle valve 6 is provided at the outlet of the mixing chamber 4. Is adjustable. The throttle valve 6 is connected to the governor lever 11 via a spring 9 so that the opening of the throttle valve 6 is adjusted and the engine speed is kept constant according to the position of the accelerator lever. In addition, a choke valve 2 for blocking inflow air is attached to an air suction port of the mixing chamber 4,
The negative pressure of the venturi section 45 is increased so that a large amount of fuel can be sucked out. The choke valve 2 has a wire 4 inserted into an outer wire 44.
3 is connected to one end, and a choke knob 46 is connected to the other end of the wire. By pulling the knob 46, the choke valve 2 is turned to the closed side to send a rich mixture, so that the engine can be easily started.
After the choke knob 46 is pulled and the engine is started, the choke knob 46 is returned and the engine is operated.

[0003]

As described above, when the engine is not warmed, it is necessary to pull the choke when starting the engine, and it is necessary to return the choke after the engine is started. For this reason, it takes time and effort to start the engine, and if the engine stops after returning to the choke after thinking that the engine has started, pull the choke again and start the engine, and then return the choke again after the engine has started There is a need. Also, if the engine is operated with the chalk forgotten, the engine may stall due to insufficient air.

[0004]

In order to solve the above problems, in a general-purpose gasoline engine equipped with a carburetor provided with a choke valve and having a governor mechanism, setting of a lever which rotates in proportion to the number of revolutions of the governor mechanism. A switch was arranged at the rotation speed position, and the switch was connected to a suction coil that operated the choke valve to the open side. In an engine equipped with a carburetor provided with a choke valve, a generator was connected to the flywheel, and the generator was connected to a suction coil that was operated to open the choke valve. Further, in a gasoline engine started by a cell motor, a switch is provided at a start position of a key switch, and the switch is connected to a battery and a suction coil which operates the choke valve to open the choke valve.

[0005]

FIG. 1 is a schematic view showing the structure of a carburetor 1 and a governor mechanism 46 according to an embodiment of the present invention. A choke valve 2 is provided at an air intake of the carburetor 1. Also, mixing chamber 4
A throttle valve 6 is rotatably provided on a pivot 7 at the outlet of the arm 7, and an arm 8 and an arm 19 are fixed to the pivot 7 so as to be relatively non-rotatable. The arm 19 includes a spring 17
The other end of the link 18 is connected to one end of an accelerator lever 20. The accelerator lever 20 is pivotally supported by a support shaft 50 so that the throttle valve 6 can be opened and closed with the rotation. A link 10 is connected to the arm 8, and the link 10 is connected to the governor lever 1 via a spring 9.
1 is connected to one end. The governor lever 11 is rotatably fixed to the pivot 16.

The governor mechanism 46 has a governor weight support 14 on an output shaft 15 which rotates according to the output of the engine.
The governor weight 12 is rotatably supported on the governor weight support 14 by a pivot 47. A sleeve 13 is slidably fitted on the shaft 15, and one end of the sleeve 13 is disposed so as to abut (or engage with) the other end of the governor lever 11. Is engaged with the governor weight 12.

In such a configuration, the rotation speed is set by rotating the accelerator lever 20. When the engine operates and the rotation speed increases and the rotation speed becomes equal to or higher than the set rotation speed, the governor weight 12 is rotated to open outward by centrifugal force, and the rotation causes the sleeve 13 to be pushed and slid. The governor lever 11 in contact with the sleeve 13 is rotated. Thereby, the link 1 is connected to the governor lever 11.
Then, the throttle valve 6 of the carburetor 1 connected via the valve 0 is rotated, and the engine speed decreases to the set speed. Further, when a load is applied to the engine and the output of the engine is reduced, the governor weight 12 rotates in a direction in which the governor weight 12 is closed inward (on the side of the axial center), the opening of the throttle valve 6 increases, and the output of the engine increases. Thus, the governor mechanism 46 keeps the engine speed at the set speed.

The carburetor 1 comprises a mixing chamber 4 and a float chamber 26 as shown in FIG.
Are connected by a main nozzle 5. In the float chamber 26, the fuel pipe 29
When more fuel is supplied and the fuel accumulates in the float chamber 26 to a certain amount, the float 30 rises, closes the discharge port of the fuel pipe 29, and the fuel in the float chamber 26 is maintained at a certain amount. Also, the float chamber 26
An overflow pipe 27 is provided therein to prevent the fuel level from rising due to backflow or excessive supply of fuel. The float chamber 26 is provided with an air vent 28 to keep the inside of the float chamber 26 at atmospheric pressure. The main nozzle 5 protrudes into the mixing chamber 4, and a main jet 48 is screwed at a lower end of the main nozzle 5. The amount of fuel injected is adjusted by the size of the holes provided in the main jet 48.

[0009] The air passing through the mixing chamber 4 reaches the outlet of the mixing chamber 4 via the venturi 45, and collides with the fuel exiting from the main nozzle 5 at the venturi 45. At the outlet, a throttle valve 6 rotatably supported by a pivot 7 is provided, and the throttle valve 6 adjusts the flow rate of the air-fuel mixture to adjust the output of the engine. An arm 8 is fixed to the pivot 7, and is connected to one end of a governor lever 11 having a substantially “L” shape by a link 10 via a spring 9. The governor lever 11 is rotatably supported by a pivot 16 and is connected to a governor mechanism (not shown). Therefore, the opening of the throttle valve 6 is adjusted so that the engine speed is constant.

A choke valve 2 for blocking the inflowing air is attached to the air suction port of the mixing chamber 4, so that the negative pressure of the venturi section 45 is increased and a large amount of fuel can be sucked out. The choke valve 2
Is pivotally supported by a pivot 3, and an arm 21 is fixed to the pivot 3 so as to be relatively non-rotatable. Arm 2
1 is connected to a spring 23 at one end thereof.
Is fixed to an engine frame or the like. The other end of the arm 21 is connected to one end of a suction coil 25 via a link 24.

The spring 23 is urged in a direction to close the choke valve 2, and when energized, the attraction coil 25 rotates the arm 21 downward via the link 24 to open the choke valve 2. It is configured. Since the suction force of the suction coil 25 is configured to be sufficiently strong, when a current flows through the suction coil 25, the suction coil can overcome the spring force and open the choke valve 2.

A switch 31 is fixedly mounted near the end of one end of the governor lever 11, and the governor lever 11 rotates and comes into contact with a contact portion 32 of the switch 31,
When the contact portion 32 is pushed in, the switch 31 is configured to conduct electricity. The switch 31 and the suction coil 25 are connected by a conducting wire. When the switch 31 is energized, a current of the generator 33 flows through the suction coil 25 and the choke valve 2 is opened. However, the generator 33
Alternatively, a battery can be used.

That is, when starting the engine, the choke valve 2 of the carburetor 1 is initially closed by the urging force of the spring 23, and when the engine crank (not shown) is rotated by a recoil starter (not shown) or the like. In this case, the negative pressure in the venturi section 48 increases, a large amount of fuel is ejected from the main nozzle 5, and a rich air-fuel mixture is supplied into the engine. Therefore, it is possible to enhance the startability of the engine, and after the engine starts,
The speed of the engine increases, and the governor lever 11 is rotated downward by the governor mechanism 46, comes into contact with the contact portion 32 of the switch 31, and conducts electricity. For this reason, the suction coil 25
The arm 21 is rotated downward while overcoming the force of the spring 23, the choke valve 2 is opened, and the concentration of the air-fuel mixture in the carburetor 1 is set to the concentration during normal operation. In this way, the choke valve 2 is closed when the engine is started, and when the output of the engine exceeds a certain level, the choke valve 2 is opened, so that normal operation can be performed.

Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic diagram of a flywheel unit showing a second embodiment of the present invention. A permanent magnet 39 is mounted on the inner side wall of the flywheel 49, and includes a generator coil 38, an ignition coil 37 connected to a capacitive discharge igniter 34 (hereinafter, a CDI unit 34), and a pulsar coil 40. Has become. A pulsar rotor 51 is provided at the center of the flywheel. When the pulsar rotor 51 comes to the ignition position, a signal generated from the pulsar coil 40 causes a capacitor provided in the CDI unit 34 by the ignition coil 37. Is discharged, and a spark is blown to the ignition plug 36 via the ignition coil 35.

The choke return power generating coil 38 is connected to the suction coil 25 via a regulator 41. For this reason, when the number of revolutions of the engine increases and the power generating coil 38 for returning the choke supplies sufficient power to the suction coil 25 to open the choke valve 2, the choke valve 2 is opened by the suction coil 25. ing.

A third embodiment of the present invention will be described. FIG. 4 is a schematic diagram showing a third embodiment of the present invention, which is applied to an engine started by a starter motor. One end of an arm 21 fixed to the pivot 3 for rotating the choke valve 2 is connected to a suction coil 25, and the other end is connected to a spring 23. The suction coil 25 is connected to a battery 53 via a switch 42 linked to a key switch (not shown). The switch 42 is configured to energize when the key is inserted into a key box (not shown) and the key is turned to the start position. When the key switch is in the ON or OFF position, the switch 42 cuts off the current to the suction coil 25,
The choke valve 2 is opened by the urging force of the spring 23. For this reason, in a rice transplanter or a carrier equipped with a battery, by the above configuration, when the key is inserted and turned to the start position, current flows to the suction coil 25, the choke valve 2 closes, and the engine starts. When the key is turned to the ON position after the engine is started, the current to the suction coil 25 is cut off, the choke valve 2 is opened, and the engine can be brought into a normal operation state. For this reason, the choke operation and the engine start operation can be performed at the same time, and it is possible to save the trouble at the start.

[0017]

As described above, the present invention has the following advantages. Specifically, in a general-purpose gasoline engine equipped with a carburetor provided with a choke valve and having a governor mechanism, a switch is arranged at a set rotational speed position of a lever that rotates in proportion to the rotational speed of the governor mechanism. Since the switch is connected to a suction coil for operating the choke valve to open the choke valve, when the engine starts and reaches the set number of revolutions, the switch is turned on and the suction coil is operated to open the chain valve,
An auto choke can be configured by installing a simple circuit.
In addition, because of the simple configuration, maintenance can be easily performed, and when a failure occurs, the cause can be easily found by checking the disconnection of the circuit and the contact portion of the switch. Further, it is possible to omit the operation of the choke at the time of starting the engine, so that the labor of the operator can be saved. Also, it is possible to prevent the engine from stalling due to forgetting to open the choke valve.

According to a second aspect of the present invention, in the engine equipped with the carburetor provided with the choke valve, the generator is connected to the flywheel, and the generator is connected to the suction coil that operates to open the choke valve. Even in general-purpose gasoline engines without batteries,
Since an auto choke can be mounted and power is generated by rotating the flywheel, the number of components that need to be newly mounted can be reduced in the embodiment of the present invention. In addition, it is possible to omit the operation of the choke at the start of the engine or after the start of the engine, so that the labor of the operator can be saved.

According to a third aspect of the present invention, in a gasoline engine started by a cell motor, a switch is provided at a start position of a key switch, and the switch is connected to a suction coil for operating a choke valve to open and a battery. The turning operation and the choke operation of the switch can be performed at the same time, and the current is supplied to the suction coil only at the time of starting the engine, so that no extra load is applied during the operation of the engine. Since it can be implemented with a simple configuration, it can be easily mounted on an existing engine. In addition, it is possible to omit the operation of the choke at the start of the engine or after the start of the engine, so that the labor of the operator can be saved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a carburetor and a governor mechanism according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a choke valve according to a first embodiment of the present invention.

FIG. 3 is a schematic view of a flywheel unit showing a second embodiment of the present invention.

FIG. 4 is a schematic diagram of an auto choke circuit and a carburetor showing a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of opening and closing a choke valve of a carburetor showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carburetor 2 Choke valve 11 Governor lever 23 Spring 25 Attraction coil 31 Switch 32 Switch contact part 38 Power generation coil 39 Permanent magnet 41 Regulator 42 Switch 49 Flywheel 53 Battery

Claims (3)

[Claims] In a general-purpose gasoline engine equipped with a carburetor provided with a choke valve and having a governor mechanism, a switch is arranged at a set rotational speed position of a lever that rotates in proportion to the rotational speed of the governor mechanism, and the switch is operated. An auto choke for a general-purpose gasoline engine, wherein the auto choke is connected to a suction coil that operates a choke valve on an opening side. 2. An engine equipped with a carburetor provided with a choke valve, wherein a generator is connected to the flywheel, and the generator is connected to a suction coil for operating the choke valve to open the side. Engine auto choke. 3. A gasoline engine started by a cell motor, wherein a switch is provided at a start position of a key switch, and the switch is connected to a suction coil for operating a choke valve to open and a battery. Auto choke.