PURPOSE: To prevent blow-by of mixture at overlapping of an intake valve and exhaust valves, and improve combustion.
CONSTITUTION: A combustion chamber 5 is formed on an intake valve 1 side out of a recessed part 7 provided on the intake valve side of the bottom face 3a of a cylinder head 3, and a recessed part 4b provided on a piston 4. The intake valve 1 and an ignition plug 8 are arranged on the recessed part 7, meanwhile two exhaust valves 8 are arranged on the bottom face 3d side of the cylinder head 3, and squish is generated in mixture from the exhaust valve 2 side. Because the wall 7b of the recessed part 7 is provided between the intake valve 1 and the exhaust valves 2, introduced mixture is hardly blown by. Further, by squish action, combustion speed becomes high, and knocking hardly generates. Exhaust is performed with the two exhaust valves. Consequently, emission can be improved, and fuel consumption quantity can be reduced. Further, operability can be improved.
YANAGI NORIO
HASEGAWA KUNIO
