| 摘要 |
PURPOSE:To enhance the efficiency of an engine and the sealability and durability of a main valve with a simple arrangement by using only one main valve so as to serve as both intake and exhaust valves, and by alternately changing over intake and exhaust passages with the use of the intake and exhaust valve. CONSTITUTION:A bevel shape main valve 4 is provided in the center section of a cylinder head 3 disposed in the upper section of a cylinder block 2 accommodating a piston 1, and an intake and exhaust pipe control valve 5 is provided surrounding the main valve 4. There are provided a passage communicated with an intake port 6 in the lower section of a range in which the intake and exhaust pipe control valve 5 vertically moves, and a passage communicated with an exhaust pipe 7 in the upper section. Further, a change-over chamber 3a is formed at a position where passages comes together, or in the rear surface of the main valve 4. Further, a cylinder device 8 for driving the valves 4, 5 is provided in the upper section of the cylinder head 3. With this arrangement, only one main valve 4 can be used so as to serve as both intake and exhaust valves, and the intake and exhaust passages are alternately changed over by means of the intake and exhaust valve 5.
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