Piston valve type layered scavenging 2-cycle engine

摘要

A piston valve type layered scavenging 2-cycle engine has a reduced engine height, is light and compact, and achieves an exhaust gas purification. An upper edge of a pilot air port provided in an inner wall of a cylinder is positioned at substantially the same height as that of an upper edge of an intake port. An extended portion extended to a lower side rather than a piston lower edge at a position opposing to the intake port is provided in a lower end portion at a position opposing to the pilot air port in the piston. An interval between the right and left extended portions is set to be larger than an outer width of a balance weight of a crank shaft. A piston groove which connects the pilot air port to the scavenging port at a time of an intake stroke is provided on an outer peripheral surface of the extended portion. A second scavenging flow passage having a simple structure is provided in a lower side of a first scavenging flow passage.