JPH09296712A - Four-stroke engine cylinder head employing hollow rotary shaft valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a cylinder head having a complex inner structure for a four-stroke engine, and ventilate a combustion chamber through a ventilation port for both intake and exhaust. SOLUTION: A hollow shaft 2 opened with an intake control opening 3, a combustion chamber-ventilation control opening 4 and an exhaust control opening 5 is attached with support bearings 6 and a timing pulley 14, and is mounted on a cylinder head opened with an intake port, an exhaust port and a combustion chamber-ventilation port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly efficient cylinder head for a 4-cycle engine.

[0002]

2. Description of the Related Art Conventionally, in a 4-cycle engine, the rotary motion of an eccentric cam is converted into a reciprocating motion, and an intake / exhaust valve is reciprocated to control the opening / closing of an intake / exhaust port.

Therefore, the structure is complicated and the number of parts is large,
There is a drawback that the inertial mass is large due to the reciprocating movement of the intake / exhaust valve and its associated components at high speeds.

In a modern four-stroke engine with a high revolution speed, this drawback is an obstacle to accurate opening / closing control of the intake and exhaust ports. In addition, ventilation of the combustion chamber is not efficient because it is used for intake and exhaust and separate openings.

[0005]

The problems to be solved are that the opening / closing control of the intake / exhaust port is controlled by the reciprocating motion of the intake / exhaust valve, and the ventilation of the combustion chamber can be performed at the same opening / exhaust port. There is no point.

[0006]

The present invention controls the opening and closing of the intake and exhaust ports by rotating the hollow shaft, so that reciprocating motion is not required and the internal mechanism can be greatly simplified. Also, by providing the intake control port, exhaust control port, and combustion chamber ventilation control port on one hollow shaft,
It is possible to ventilate the combustion chamber through the intake and exhaust openings. This effectively ventilates the combustion chamber and realizes accurate opening / closing control of the intake and exhaust ports.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one embodiment of the device of the present invention, which is a hollow shaft having intake, exhaust, ventilation, and control ports opened, and a timing pulley and a support bearing attached.
Reference numerals are the same as those in each figure.

FIGS. 3 and 4 show a four-cycle single-cylinder engine equipped with a cylinder head using two hollow shafts. Since the subject of the present invention is the method for controlling intake and exhaust, a description of the ignition and lubrication system will be omitted.

The intake, compression, explosion, exhaust, and each stroke will be described with reference to FIG. 4. At the start of the intake stroke, the rotation of the hollow shaft 2 causes the intake control port 3 to move and the intake port 7 to open. The combustion chamber ventilation port 9 is already open and the piston 10
The air-fuel mixture is inhaled by the negative pressure generated by the fall of. At the end of the intake stroke, the combustion chamber ventilation control port 4 moves to close the combustion chamber and shift to the compression stroke. Each opening is closed due to movement of each control port during compression, explosion, and each stroke. At the start of the exhaust stroke, the combustion chamber ventilation port 9 and the exhaust port 8 start opening due to the movement of the combustion chamber ventilation control port 4 and the exhaust control port 5, and the combusted air-fuel mixture is exhausted by the positive pressure generated by the rise of the piston 10. At the end of the exhaust stroke, the combustion chamber ventilation port 9 remains open and shifts to the intake stroke.

The rotation of the hollow shaft 2 is driven by the drive belt 13
The speed is reduced to half of the crankshaft 12 by the timing pulley 14 via. The position and shape of each control port are changed and adjusted according to the desired characteristics.

As described above, since the cylinder head of the present invention can perform intake and exhaust with each hollow shaft, the area of the combustion chamber ventilation port can be made larger than before.
Further, since the number of parts is small, it is useful for improving productivity and reducing failures.

[Brief description of drawings]

FIG. 1 is a hollow shaft fitted with a timing pulley and a support bearing.

FIG. 2 is a development view of a hollow shaft.

FIG. 3 is a diagram of a 4-cycle single cylinder engine equipped with a rotary valve cylinder head having two hollow shafts mounted therein.

FIG. 4 is a cross-sectional view in which each opening of the cylinder head can be seen.

FIG. 5 is an explanatory view showing intake, compression, explosion, exhaust, and each stroke with FIG. 3 as a sectional view.

[Explanation of symbols]

 1 Cylinder Head 2 Hollow Shaft 3 Intake Control Port 4 Combustion Chamber Ventilation Control Port 5 Exhaust Control Port 6 Support Bearing 7 Intake Port 8 Exhaust Port 9 Combustion Chamber Ventilation Port 10 Piston 11 Spark Plug 12 Crank Shaft 13 Drive Belt 14 Timing Pulley 15 Crank Case 16 Cylinder 17 Connecting rod

Claims (1)

[Claims] 1. A cylinder head characterized in that an intake control port, an exhaust control port, and a combustion chamber ventilation control port are provided on a hollow shaft, and opening / closing of a 4-cycle engine is controlled by rotation of the hollow shaft.