JPH1122471A - Intermittent explosion two-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high a output without blowby of an air-fuel mixture. SOLUTION: A two-cycle engine having an exhaust port 7 to open and close by a piston 3, a scavenging port 9 and a suction port is provided with an air-fuel mixture passage 11 where air-fuel mixture passes and an air passage 13 where air passes on the suction port and a rotary shaft valve in the passage. Thereafter, the rotary shaft valve 15 alternately opens the air-fuel mixture passage and the air passage for each rotation of a crankshaft 4, alternately sucks air-fuel mixture and air into a crankcase, pre-loads them and supplies them to a cylinder, and when air-fuel mixture enters the cylinder 2, ignites and explodes, a rotary shaft valve 14 opens an exhaust passage 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an exhaust port with a piston,
The present invention relates to a two-stroke engine that opens and closes a scavenging port and an intake port, sucks air from the intake port into a crank chamber, and supplies a pre-pressurized mixture to a cylinder.

[0002]

2. Description of the Related Art In a conventional two-stroke engine, when an exhaust port is opened by a piston, waste gas flows out instantaneously, and then when a scavenging port is opened, an air-fuel mixture in a crank chamber enters a cylinder through a scavenging passage. It is like that.

[0003]

However, in the conventional two-stroke engine, since the exhaust port is widely opened,
The period from when the piston begins to open the exhaust port to when it closes is long, and even during compression, the exhaust port is open, so there is much blow-through of the air-fuel mixture, and the amount of compression remaining in the cylinder is reduced, so high output I can't hope.

Accordingly, an object of the present invention is to provide a two-stroke engine capable of improving the filling of an air-fuel mixture into a cylinder and discharging only waste gas from the cylinder.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a mixture passage for air-fuel mixture and an air passage for air at an intake port, and a rotating shaft which rotates once for every two rotations of a crankshaft. Valves are provided in the mixture passage and the air passage, and the rotary shaft valve opens the mixture passage and the air passage alternately for each rotation of the crankshaft. The mixture and air pre-pressurized in the crank chamber are alternately supplied to the cylinder when the piston descends and the piston descends, so that one ignition explosion occurs during two revolutions of the crankshaft. When only air is in the cylinder, explosion does not occur and it becomes residual air. Subsequently, the air-fuel mixture blows out from the scavenging port due to the preload in the crank chamber. A scavenging port is provided toward the combustion chamber to guide the air-fuel mixture into the combustion chamber, thereby preventing misexplosion. The exhaust passage is intended to provide an intermittent explosive two-stroke engine which is opened when an ignition explosion occurs and closed when no ignition explosion occurs.

[0006] In the intermittent explosive two-cycle engine of the present invention, when the piston rises, the pressure in the crank chamber becomes low, and then the intake port opens, either the mixture passage or the air passage opens, and, for example, the mixture passage becomes open. When open, the air passage is closed and the mixture is sucked into the crankcase. After the piston passes the top dead center, it does not explode with air only and does not exhaust. Subsequently, the scavenging port opens, but since there is residual air in the cylinder last time, a scavenging port is provided toward the combustion chamber to guide the air-fuel mixture to the combustion chamber. Prevent mistake explosion. Then, although the piston moves to the upward stroke past the bottom dead center, the exhaust passage is closed by the rotary shaft valve, and no air-fuel mixture is pushed out from the exhaust port. Eventually, the pressure in the crank chamber becomes low, and then the intake port opens. At this time, since the mixture passage is closed and the air passage is opened, air is sucked into the crank chamber. The air is compressed in the crank chamber during the downward stroke of the piston due to the explosion, and is ejected to the cylinder when the scavenging port is opened. The air blown into the cylinder remains in the cylinder. Subsequently, as the piston rises, the pressure in the crank chamber becomes low, and the intake port opens. At this time, since the air passage is closed and the mixture passage is opened, the mixture is sucked into the crank chamber. Thus, the mixture and the air alternately enter the crank chamber and are supplied to the cylinder, so that when the mixture is supplied to the cylinder and compressed by the piston, an ignition explosion occurs, and when the air is supplied to the cylinder chamber, There is no ignition explosion, and the next compression can be increased to produce high output.

The rotary shaft valve is pushed into the exhaust passage at the exhaust port,
The intake port is provided with an air passage at an upper portion of the intake port and a mixture passage at a lower portion thereof, and is coaxial so as to make one rotation for every two rotations of the crankshaft. However, when a rotary shaft valve is provided in each of the air passage and the mixture passage, each rotary shaft valve makes one rotation per rotation of the crankshaft.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a two-stroke engine according to the present invention will be described below with reference to the drawings. 1 is a crankcase, 2 is a cylinder, 3 is a piston, 4 is a crankshaft,
5 is a connecting rod, 6 is a spark plug, 7 is an exhaust port, 8 is an exhaust path, 9 is a scavenging port, 10 is a mixture port, 11 is a mixture path,
12 is an air port, 13 is an air passage, 14 is a rotary shaft valve, 15
Is a rotary shaft valve. A vaporizer is connected to the mixture passage 11, and a flow control valve is provided in the air passage 13.

[0009]

As described above, according to the present invention, the mixture passage and the air passage are provided in the intake port, and each passage is provided for every two rotations of the crankshaft.
A rotating shaft valve that rotates is provided so that both passages are opened alternately, so air-fuel mixture and air enter the cylinder alternately.When air-fuel mixture enters, the piston ignites and explodes at the top dead center of the piston. There is no explosion when it enters, and the air remaining in the cylinder helps to highly compress the air-fuel mixture that has entered the cylinder next time. Qi is highly compressed in the cylinder and high output is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view.

[Explanation of symbols]

 Reference Signs List 7 exhaust port 8 exhaust path 9 scavenging port 10 mixture port 11 mixture path 12 air port 13 air path 14 rotary shaft valve 15 rotary shaft valve

Claims (1)

[Claims] In a two-cycle engine having an exhaust port, a scavenging port, and an intake port opened and closed by a piston, and a crank chamber communicating with a cylinder through a scavenging passage, an air-fuel mixture passage and air flow through the intake port. A rotary shaft valve is provided in the passage, and the rotary shaft valve rotates once every two rotations of the crankshaft to alternately open the mixture passage and the air passage. The passages are opened alternately, and the air-fuel mixture and the air are alternately sucked into the crank chamber, pre-pressurized and supplied to the cylinder, an exhaust passage is provided in the exhaust port, a rotary shaft valve is provided in the exhaust passage, and the air-fuel mixture is provided. An intermittent explosive two-stroke engine characterized in that a rotary shaft valve opens an exhaust passage when an ignition explosion occurs in a cylinder.