JPH0623722Y2 - 4-cycle engine with fuel reduction device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a four-cycle engine for a model airplane, and to a four-cycle engine with a fuel reduction device improved to prevent engine trouble during somersault flight.

[Conventional technology]

Conventionally, as a mixture supply device for a four-cycle engine for a model, a mixture intake hole and a mixture air supply hole are provided at appropriate positions in a crank chamber of a cylinder having an intake and exhaust port, and the mixture supply hole and the intake port of the cylinder are mixed. Connected by an air supply pipe with a tank, the valve body opens and closes the intake hole and the air supply hole by raising and lowering the piston, expands the air-fuel mixture that can be sucked into the crank chamber during the exhaust and compression strokes, and through the air vent hole during the suction stroke to the air-fuel mixture tank. There is one that is pumped and sucked into the combustion chamber of the cylinder.

[Problems to be solved by the device]

By increasing the mixture tank of the above-mentioned conventional mixture supply device, it is possible to hold as much mixture as that,
Even after opening the intake valve and inhaling the air-fuel mixture, the pressure drop in the air-fuel mixture tank can be reduced and the output can be improved, but if the air-fuel mixture tank is enlarged, the inner surface area increases,
At the middle or low speed of the engine, a part of the air-fuel mixture adheres to the large inner surface and changes into liquid fuel, and when the model airplane flips over and the engine is inverted, the top of the tank is facing down. The liquid fuel accumulates, and when the engine returns to the upright position, the liquid fuel that has accumulated on the top of the tank rapidly flows into the intake port of the cylinder, causing fuel fog on the spark plug, and stopping the engine (stalling) It has not been possible to increase the size of the air-fuel mixture tank because it causes complete combustion.

In order to solve the above-mentioned problems in the air-fuel mixture supply device for a 4-cycle engine, this invention enlarges the air-fuel mixture tank, but connects the air-fuel mixture tank and the crank chamber with a reducing pipe equipped with a check valve. Liquid fuel generated in the air-fuel mixture tank and accumulated at the top of the air-fuel mixture tank when the engine is inverted is used to return the liquid fuel to the crank chamber by opening the check valve by utilizing the differential pressure between the tank and the crank chamber. An object of the present invention is to provide a four-cycle engine with a fuel reduction device that prevents fogging and engine stall.

[Means for Solving the Problems]

In order to achieve the above object, a four-cycle engine with a fuel reducing device of the present invention is provided with a large-capacity air-fuel mixture tank in an air supply pipe connecting a crank chamber of a cylinder and an intake port, and a top portion of the air-fuel mixture tank. It is connected to a proper place in the crank chamber with a reducing pipe, and the reducing pipe is equipped with a check valve that closes when the crank chamber has a positive pressure and opens when the crank chamber has a negative pressure. The present invention relates to a technical means for returning the liquid fuel accumulated at the top portion to the crank chamber through a reducing pipe by using the negative pressure of the crank chamber, and prevents the fuel from being fogged on the ignition plug and preventing engine trouble.

[Action]

According to this invention, by making the mixture tank of the mixture supply device large and large in size, the mixture stays in the tank at a medium or low speed for a little longer, so that the inner surface of the tank becomes larger. Part of the air-fuel mixture adheres and changes to liquid fuel. The liquid fuel does not flow down to the crank chamber through the air pipe when the engine is upright, but it collects at the top when the engine is inverted, so the negative pressure in the crank chamber is used to open the check valve and reduce the fuel. It is possible to reduce the liquid fuel to the crank chamber through a pipe so that liquid fuel does not remain on the top of the air-fuel mixture tank, and when the engine changes its posture from an upright state to an upright state, there is no sudden inflow of liquid fuel into the combustion chamber. Fogging on the spark plug can be prevented, and engine stop (stalling) can be prevented.

〔Example〕

 Examples will be described with reference to the drawings.

FIG. 1 shows an upright posture of the 4-cycle engine, and FIG. 2 shows the same upside-down state.

1 and 2, 1 is a cylinder of a model 4-cycle engine, 2 is its crank chamber, 3 is an intake port for an intake valve, 4 is a mixture tank, 5 is a crank chamber 2 and an intake port 3 of a cylinder. An air supply pipe 6 for communicating with the air-fuel mixture is a piston, and is an air-fuel mixture supply device capable of supplying the air-fuel mixture to the intake port through the air-supply pipe and the air-fuel mixture tank by raising and lowering the piston 6.

In this air-fuel mixture supply device, the air-fuel mixture tank 4 is large in size so that a large amount of air-fuel mixture can be retained, and the air-fuel mixture tank 4 is opened even after the intake valve 9 of the intake port 3 is opened to inhale the air-fuel mixture. Air mixture remains to reduce pressure drop,
The air pressure is relatively increased to improve the output.

The large air-fuel mixture tank 4 is located on the upper side portion of the cylinder 1, and the upper side portion of the air-fuel mixture tank 4 and the intake port 3 are connected by an air supply pipe 5. The top of this large mixture tank 4
When 4a is a shallow recess, the tank 4 when the engine is upside down
The fuel that has turned into a liquid inside is collected at the top portion 4a of the air-fuel mixture tank 4 which has been inverted.

Reference numeral 7 is a fuel reduction pipe that connects the top portion 4a of the air-fuel mixture tank 4 and the crank chamber 4, and is closed during positive pressure in the crank chamber,
A check valve 8 that opens when the crank chamber has a negative pressure is provided. In the embodiment, since the differential pressure is too large when the reducing pipe 7 is directly connected to the crank chamber 4, the reducing pipe 7 is connected to the crankshaft 10 of the crank chamber 4 at a midpoint of the reducing pipe 7. A check valve 8 is provided, which is normally closed by positive pressure in the crank chamber. When the pressure on the crank chamber side falls below the pressure in the air-fuel mixture tank and becomes negative, the check valve 8 is opened by the differential pressure, and In the upright state, the air-fuel mixture in the air-fuel mixture tank 4 is returned, and in the inverted state of the engine, the liquid fuel accumulated at the top is returned to the crankshaft portion. Return tube 7
Is connected to a position where the crankshaft 10 is not sufficiently lubricated as in the embodiment, not only the return action of the air-fuel mixture and the liquid fuel but also the lubrication and rust preventive action of the air-fuel mixture and the liquid fuel can be performed.

In the above embodiment, the reducing pipe 7 is connected to the portion of the crankshaft, but the present invention is not limited to this, and it may be connected to another portion of the crank chamber where the negative pressure is low.

In addition, 11 is a mixture air intake hole, 12 is a mixture air supply hole, 13 is a rotary valve that opens and closes the intake hole 11 and the air supply hole 12 by moving the piston 6 up and down, 14 is a flywheel, 15 is a cylinder exhaust valve exhaust port, 16 is a spark plug.

According to the four-cycle engine of the present invention, when the piston moves up and down, the air-fuel mixture in the crank chamber 2 is retained in the large air-fuel mixture tank 4 through the air supply pipe 5 and is supplied to the intake port 3 in the intake stroke. Air is supplied without liquefaction because it stays in the tank for a short time, and the mixture stays in the tank a little longer at medium to low speeds, so some of the mixture touches the large surface area of the tank to cool. By the action, it is returned to liquid fuel, and when the engine is upright, the liquid fuel flows from the tank to the crank chamber through the air supply pipe 5, so there is no problem with air supply, but when flying the model airplane by somersault When the engine is upside down, liquid fuel accumulates in the top part 4a of the mixture tank 4 which is on the bottom side as shown in FIG. The pressure generated causes a pressure difference between the air-fuel mixture tank and the crank chamber to open the check valve 8, and returns the accumulated fuel to the crank chamber through the reducing pipe 7, so that the engine is in the upright state rather than the inverted state. Even if the posture is changed to, the liquid fuel does not flow into the intake port, and the air-fuel mixture can be sent to the intake port, so stable somersault flight can be performed.

[Effect of device]

According to this invention, although the air-fuel mixture tank of the air-fuel mixture supply device has a large volume and is large, since the top of the air-fuel mixture tank and the crank chamber are connected by a reducing pipe and a check valve is provided, the air-fuel mixture of the air-fuel mixture tank is Part of the liquid fuel can be returned through the reduction pipe by opening the check valve by utilizing the pressure difference between the tank and the crank chamber. Especially, when the model airplane is somersault and the engine is upside down, it occurs in the air-fuel mixture tank. The liquid fuel accumulated at the top can be returned to the crank chamber by opening the check valve with the negative pressure of the crank chamber, so the accumulated liquid fuel does not suddenly flow into the intake port even if the posture of the engine changes. Therefore, it is possible to prevent fog and stalling of the liquid fuel of the spark plug, to prevent engine trouble during somersault flight, to ensure stable flight, and to increase the output power by increasing the size of the air-fuel mixture tank. It can be achieved.

[Brief description of drawings]

1 and 2 show a four-cycle engine with a fuel reduction device according to the present invention. FIG. 1 is a schematic sectional view of the engine in an upright state, and FIG. 2 is a schematic sectional view of the engine in an inverted state. is there. 1 ... Cylinder, 2 ... Crank chamber, 3 ... Intake port, 4 ... Mixture tank, 4a ... Top part, 5 ... Air supply pipe, 6 ... Piston, 7 ...
Return pipe, 8 ... Check valve.

Claims (1)

[Scope of utility model registration request] 1. A large air-fuel mixture tank (4) having a large capacity is provided in an air supply pipe (5) connecting a crank chamber (2) of a cylinder (1) and an intake port (3), and the air-fuel mixture tank (4) is provided. The top part (4a) of 4) is connected to the proper position of the crank chamber (2) by a reducing pipe (7), and the reducing pipe (7) is closed when the crank chamber has a positive pressure and opened when the crank chamber has a negative pressure. Equipped with a check valve (8),
It occurs in the air-fuel mixture tank (4) and the top (4
A four-cycle engine with a fuel reduction device characterized in that the liquid fuel accumulated in a) can be reduced to the crank chamber through a reduction pipe (7) by using the negative pressure of the crank chamber.