JPH0640358U - Air-cooled gasoline engine intake system - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a technique that can be implemented at low cost as a technique for preventing an external cylinder explosion. [Configuration] An intake passage opening / closing valve 10 is attached to the intake pipe 6. The intake passage opening / closing valve 10 includes a valve body 11 that opens and closes the intake passage,
A wind receiving plate 13 provided outside the intake pipe 6 and interlockingly connected to the valve body 11, and a biasing spring 1 for biasing the valve body 11 to the closing side.
4 and. During operation of the engine, the wind receiving plate 13 resists the urging force of the urging spring 14 to receive the fan wind force of the cooling fan 5 to open the valve body 11 to operate the urging force. The spring 14 overcomes the wind force less than the fan wind force at the time of starting the engine, and closes the valve body 11.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an air intake system for an air-cooled gasoline engine, and more particularly to a technique for preventing external explosion.

[0002]

[Prior art]

 In a cylinder explosion, when the gasoline engine is stopped, the crankshaft is rotated by the inertial rotational force of the flywheel, and the piston acts as a pump, which causes the fuel to be sucked out of the carburetor and burned. It occurs because it enters the muffler through the chamber and is ignited and exploded by the heat of the muffler. As a technology to prevent this out-of-cylinder explosion, conventionally, for example, a carburetor is equipped with a solenoid-operated fuel passage opening / closing valve, and the solenoid is automatically activated when the engine is stopped, so that the fuel passage in the carburetor is connected to It is configured to be closed by a passage opening / closing valve to prevent fuel supply.

[0003]

[Problems to be solved by the device]

 In the conventional example described above, since a fuel passage opening / closing valve that operates by a solenoid is attached to the carburetor, a solenoid control circuit is required, and the structure is complicated and the cost is high. The present invention has been made in consideration of such circumstances, and an object thereof is to provide a technique that can be implemented at low cost by omitting a fuel passage opening / closing valve that is operated by a solenoid.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the means adopted by the present invention is that the crankshaft 1a is projected from the front surface of the crankcase 1, the cooling fan 5 is fixed to the projected crankshaft 1a, and the front surface of the cylinder head 2 is fixed. The intake port 3 is opened to the intake port 3, the intake pipe 6 is connected to the intake port 3, the carburetor 7 and the air cleaner 8 are sequentially connected to the intake pipe 6, and the cooling fan 5 and the intake pipe 6 are connected to the fan. In an intake system for an air-cooled gasoline engine covered with a cover 4, an intake passage opening / closing valve 10 is attached to the intake pipe 6, and the intake passage opening / closing valve 10 includes a valve body 11 for opening / closing an intake passage 6a. The wind receiving plate 13 is provided outside the intake pipe 6 and includes a wind receiving plate 13 that is interlocked with the valve body 11 and a biasing spring 14 that biases the valve body 11 toward the closing side. Is the biasing spring 1 when the engine is operating. Against the urging force of the cooling fan 5, the valve body 11 is opened by receiving the fan motive force of the cooling fan 5, and the urging spring 14 generates a motive force less than the fan motive force at the time of starting the engine. It is characterized in that it is set to a biasing force that overcomes and closes the valve body 11.

[0005]

[Function of the device]

 The wind receiving plate 13 is provided outside the intake pipe 6 and is interlocked with the valve body 11. The wind receiving plate 13 resists the urging force of the urging spring 14 while the engine is in operation and the cooling fan In response to the cooling air A generated by the fan 5, the valve body 11 is opened to open the intake passage 6a. Further, when the engine is stopped, the engine speed is lower than the engine speed during the starting operation, so that the wind force of the cooling fan 5 is weakened and the wind receiving plate 13 loses the urging force of the urging spring 14. The valve body 11 is closed.

That is, by competing the wind force received by the wind receiving plate 13 when the engine is stopped with the urging force of the urging spring 14, the intake passage 6a is closed by the valve body 11 when the engine is stopped to supply the fuel. Block. This prevents the fuel sucked from the carburetor from entering the muffler through the combustion chamber, and prevents the out-of-cylinder explosion caused by ignition of the fuel in the muffler.

[0007]

[Effect of device]

 In the present invention, when the engine is stopped, the urging force of the urging spring 14 overcomes the wind force received by the wind receiving plate 13 to close the valve body 11 and close the intake passage 6a with the valve body 11 to prevent fuel supply. Therefore, compared with the conventional carburetor in which a fuel passage opening / closing valve operated by a solenoid is attached, the carburetor can be implemented with a simple structure and at a low cost.

[0008]

Embodiment An embodiment of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a front view of a vertical air-cooled gasoline engine according to an embodiment of the present invention, and FIG. 2 is a cross-sectional plan view of its intake / exhaust ports.

In the basic configuration of this embodiment, a crankshaft 1a is provided so as to project from the front of the crankcase 1, a cooling fan 5 is fixed to the projecting crankshaft 1a, and an intake port 3 is provided at the front of the cylinder head 2. An opening is opened, an intake pipe 6 is connected to the intake port 3, a carburetor 7 and an air cleaner 8 are sequentially connected to the intake pipe 6, and the cooling fan 5 and the intake pipe 6 are covered with a fan cover 4. Has been done. Reference numeral 9 in FIG. 1 is a fuel float chamber, reference numeral 2a in FIG. 2 is a combustion chamber, 27 is an exhaust pipe, and 27a is an exhaust passage.

An intake passage opening / closing valve 10 is attached to the intake pipe 6, and the intake passage opening / closing valve 10 is provided outside the intake pipe 6 and a butterfly type valve body 11 that opens and closes the intake passage 6 a. The wind receiving plate 13 is interlocked with the valve body 11, an urging spring 14 for urging the valve body 11 toward the closing side, and a stopper 15 for receiving the wind receiving plate 13. During operation of the engine, the wind receiving plate 13 resists the urging force of the urging spring 14 and receives the fan wind force of the cooling fan 5 to open the valve body 11 to operate the stop member 15. Then, the valve element 11 is set to the fully open position and the intake passage 6a is opened.

On the other hand, the biasing spring 14 is set to a biasing force that closes the valve body 11 by overcoming the wind force that is less than the fan wind force during the engine starting operation. Therefore, when the engine is stopped, the rotational speed of the engine becomes lower than the rotational speed during the starting operation, the wind force of the cooling fan 5 is weakened, and the wind receiving plate 13 loses the urging force of the urging spring 14 and the intake passage 6a. Is closed by the valve element 11, and the supply of fuel is blocked.

That is, the fuel sucked out from the carburetor 7 is prevented from entering the muffler 28 via the combustion chamber 2a, and the out-of-cylinder explosion caused by the ignition of the fuel in the muffler 28 is prevented. As a result, the carburetor can be implemented with a simple structure and at a low cost, as compared with the conventional carburetor in which a solenoid-operated fuel passage opening / closing valve is attached.

As shown in FIGS. 1 and 3, the air cleaner 8 is divided by a cleaner element 16 into an outside air introducing chamber 17 and an air purifying chamber 18. The air purifying chamber 18 has a check valve 20 and a communication port. A gas return pipe 26 for purified air blow-by gas is connected via a port 25, and is configured to introduce purified air blow-by gas from a breather device (not shown) into the air purification chamber 18. The check valve 20 is attached in view of the fact that the engine may be operated with the gas return pipe 26 of the purified blow-by gas remaining disconnected from the communication port 25 due to a connection error during maintenance work. This is to prevent dust and dirt from being sucked into the purifying chamber 18.

That is, the check valve 20 includes a ball-shaped check valve body 21, a pressing spring 22 for pressing the check valve body 21 to close the communication port 25, a pressing spring 22 and It is composed of the guide cylinder 23 of the check valve body 21 and configured to open the check valve body 21 against the pressing spring 22 by the pressure of the purified air blow-by gas from the breather device while the engine is operating. Has been done.

FIG. 4 is a cross-sectional view of essential parts showing a modified example of the check valve 20 of the air cleaner 8. This embodiment differs from the check valve 20 of FIG. 3 in that the spring plate member 21 a is used to close the communication port 25 in place of the pressing spring 22 and the check valve body 21, and the structure is simple. It has become. Although the present invention has been described in the above embodiment as being applied to a vertical engine, the present invention can also be applied to a horizontal engine.

[Brief description of drawings]

FIG. 1 is a front view of a vertical air-cooled gasoline engine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional plan view of intake / exhaust ports of a vertical air-cooled gasoline engine according to an embodiment of the present invention.

FIG. 3 is a sectional view of a main part of an air cleaner.

FIG. 4 is a cross-sectional view of essential parts showing a modified example of the check valve of the air cleaner.

[Explanation of symbols]

1 ... Crank case, 1a ... Crank shaft, 2 ...
Cylinder head, 3 ... Intake port, 4 ... Fan cover, 5 ... Cooling fan, 6 ... Intake pipe,
6a ... Intake passage, 7 ... Vaporizer, 8 ... Air cleaner, 10 ... Intake passage opening / closing valve, 11 ... Valve body, 13 ... Wind receiving plate, 14 ... Energizing spring.

Claims (1)

[Scope of utility model registration request] 1. A crankshaft (1a) is projected from the front of the crankcase (1), a cooling fan (5) is fixed to the projected crankshaft (1a), and the front of the cylinder head (2) is fixed. The intake port (3) is opened, the intake pipe (6) is connected to the intake port (3), and the carburetor (7) and the air cleaner (8) are sequentially connected to the intake pipe (6). Install the cooling fan (5) and the intake pipe (6) in the fan cover (4)
In an intake system for an air-cooled gasoline engine that is configured by covering with, an intake passage opening / closing valve (10) is attached to the intake pipe (6), and the intake passage opening / closing valve (10) opens and closes the intake passage (6a). A valve body (11), a wind receiving plate (13) provided outside the intake pipe (6) and interlockingly connected to the valve body (11), and a biasing force for biasing the valve body (11) to the closing side. Spring (1
4) and the wind receiving plate (13) resists the urging force of the urging spring (14) while the engine is operating, and the fan wind force of the cooling fan (5). In response to this, the valve body (11) is opened, and the biasing spring (14) overcomes the wind force that is less than the fan wind force during engine start-up operation and closes the valve body (11). An air-cooled gasoline engine intake device characterized by being set to a biasing force.