Patent ID: 6367431
Filing Date: 2002-04-09
Classification: F02B

Abstract:
An internal combustion engine comprising:a crankcase having a crank chamber; an intake port for providing a fuel mixture to the crankcase; a cylinder having an inner wall and a combustion chamber, the cylinder being mounted to the crankcase; an exhaust port in the cylinder for expelling exhaust gases; a scavenging port in the cylinder for communication between the crank chamber and the combustion chamber; a piston having an outer surface and being reciprocally moveable in the cylinder and positionable to open or close the scavenging port and the exhaust port as the piston reciprocates in the cylinder; and a groove with an open cross-section formed in the piston's outer surface, the groove having first and second ends and being open along its entire length toward the inner wall of the cylinder between the first and second ends.