JPS6330486B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a four-cycle engine equipped with an intake valve and an exhaust valve, in which an intake port of an exhaust passage provided with an intake valve and an exhaust port of an exhaust passage provided with an exhaust valve are provided. It is installed at the top of the cylinder, and the intake and exhaust ports are opened and closed by a piston to prevent fresh air from leaking from the valve gap, and air is pushed to the bottom of the cylinder for an appropriate period near the bottom dead center of the piston. To provide an engine in which the engine output can be adjusted by adjusting the air amount.

In the engine of the present invention, an intake port and an exhaust port are provided at the top of the cylinder and are opened and closed by a piston, an intake valve is provided in the intake path leading to the intake port, and an exhaust valve is provided in the exhaust path leading to the exhaust port. The exhaust valve is a four-stroke engine that operates in conjunction with the crankshaft, and the crank chamber is sealed. The crank chamber and the inside of the cylinder can communicate with each other through a passage, and the passage is opened and closed by a piston. In addition, a passage is provided for air to flow into the crank chamber when the crank chamber becomes negative pressure due to the rise of the piston, and an air flow control valve is provided in the passage. The amount of air entering the crank chamber can be adjusted by hand or foot.

Because of this structure, there is no intake or exhaust port in the combustion chamber that is formed when the piston reaches near top dead center, so there is no risk of air-fuel mixture leaking from the exhaust valve during high compression and high rotation. do not have. In a conventional 4-stroke engine, the intake and exhaust valves are closed when the piston is at high compression, but the exhaust valve has a tendency to adhere tightly to the valve seat due to carbon build-up and the valve spring jumping at high speeds. As a result, highly compressed air-fuel mixture leaks from the exhaust valve gap, reducing output, wasting fuel, and causing pollution. However, in the engine of the present invention, the intake port and exhaust port are opened and closed by a piston, and the piston further compresses the air-fuel mixture even after the intake port and exhaust port are closed until the engine reaches top dead center. That is, since the intake port and the exhaust port are closed during the compression stroke, the air-fuel mixture does not leak out of the cylinder during the compression stroke. A very small amount of blow-by gas enters the crank chamber, but the explosion causes the piston to descend, the piston opens the exhaust port, and then the exhaust valve opens, exhaust gas is discharged at a tremendous speed, and the piston descends, prepressurizing the air in the crank chamber. When the air passage leading to the cylinder is opened, the preloaded air passes through the passage and enters the lower part of the cylinder, that is, the top of the piston, and the cylinder is filled with waste air in the upper layer and air in the lower layer, and the piston reaches the top dead center. By this time, the exhaust gas has been completely forced out of the exhaust port and through the exhaust valve by the air forced in from the crankcase. In conventional engines, the exhaust valve is open until the piston reaches top dead center to discharge waste gas, but in the engine of the present invention, the exhaust port is closed by the piston near top dead center before reaching top dead center. Therefore, in order to allow all the waste air to come out by the time the exhaust port is closed by the piston, the crank chamber is made into an air pre-pressure chamber, and the pre-pressurized air is forced into the cylinder from below until the exhaust port opens. During this time, pre-pressurized air is used to push out the waste air. A portion of the precompressed air exits the cylinder along with the waste air. When the piston closes the exhaust port, only air remains in the cylinder.

Next, embodiments of the present invention will be described with reference to the drawings.

1 is a cylinder, 2 is a cylinder head, 3 is a piston, 4 is a crank, 5 is an intake port through which an intake passage opens into the cylinder, 6 is an intake valve provided in the intake passage and linked to the crankshaft via a cam, 7 8 is an exhaust port whose exhaust path opens into the cylinder; 8 is an exhaust valve that is linked to the crankshaft via a cam provided in the exhaust path; 9 is a sealed crank chamber; 10
11 is an opening in the cylinder of the passage 10; 12 is a passage through which air flows into the crank chamber 9; 13 is a passage connected to the passage 12 to adjust the amount of air passing through the passage 12. The air flow control valve 1 is an air flow control valve provided.
3 is adapted to be operated by hand or foot via a cable, lever, etc. The timing of opening and closing of the intake valve 6 and exhaust valve 8 and the passages 10 and 12 are determined by the piston 3.
An example of when the switch is opened and closed is shown in FIG. Near top dead center, the piston closes the intake and exhaust ports, so there is no leakage from the valve gap. Further, fuel and air are mixed in the carburetor, the mixture is drawn into the cylinder by opening the intake valve 6 and the intake port 5, and when the piston descends and the opening 11 of the passage 10 opens, the pre-pressurized air is released in the crank chamber 9. follows the lower part of the cylinder and enters below the mixture layer. Inside the cylinder, a suitable air-fuel mixture is forced into the upper part and air is forced into the lower part, where it is compressed and an ignition explosion takes place. Around the time the exhaust valve 8 opens, the opening 11 of the passage 10 opens, and the air pre-pressurized in the crank chamber 9 enters the lower part of the cylinder.
By the time the piston reaches top dead center, most of the waste gas has been exhausted and only air remains in the combustion chamber of the cylinder. When the air flow control valve 13 is opened wide, the amount of air entering the crank chamber 9 increases, and therefore the amount of air entering the cylinder also increases. The more air that enters the cylinder, the higher the compression pressure of the air-fuel mixture inside the cylinder, and the higher the output.

The engine of the present invention has an exhaust port in the cylinder wall and an exhaust valve in the exhaust path leading to the exhaust port, and the exhaust port is closed as soon as compression starts, and when the compression is still low, the exhaust port is closed again by the piston. At high compression, the combustion chamber has no holes through which the mixture can leak, as mentioned above, and there is no leakage of the mixture from the exhaust port. In currently used engines, leakage from the intake port is inhaled along with new air-fuel mixture during the intake stroke, but air-fuel mixture leakage from the exhaust port or exhaust valve is not inhaled and is discharged into the outside air, causing pollution. A small amount of blow-by gas is pushed into the cylinder along with fresh air near bottom dead center and completely combusted. The feature of the engine of the present invention is that unlike conventional engines, the combustion chamber formed when the piston reaches top dead center has no intake port, exhaust port, or valve at all, so there is no air-fuel mixture leakage and therefore no pollution. The fuel efficiency is also very good. However, since the exhaust port is located lower than in a conventional engine, it seems that more of the waste gas pushed out by the piston remains, but since the crank chamber is sealed, the fresh air compressed in the crank chamber is This promotes gas emissions. As described above, the engine of the present invention is characterized in that there are no valves in the combustion chamber, and the output is adjusted by adjusting the compression level.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along line A--A in FIG. 1 is the cylinder, 2 is the cylinder head, 3
is a piston, 4 is a crank, 5 is an intake port, 6 is an intake valve, 7 is an exhaust port, 8 is an exhaust valve, 9 is a crank chamber, 10 is a passage, 11 is an opening, 12 is a passage, 13
is an air flow control valve.

Claims (1)

[Claims] 1 An intake port and an exhaust port that are opened and closed by a piston are provided at the top of the cylinder, an intake valve is provided in the intake path leading to the intake port, an exhaust valve is provided in the exhaust path leading to the exhaust port, and the intake valve and exhaust valve A passage that operates in conjunction with the crankshaft and communicates the sealed crank chamber with the cylinder.The passage is opened and closed by a piston, and air flows into the crank chamber, which becomes negative pressure when the piston rises. A four-stroke engine, which is equipped with an air flow control valve that is operated manually or by foot in its passage.