PISTON VALVE TYPE LAYERED SCAVENGING 2-CYCLE ENGINE

摘要

A piston valve type layered scavenging 2-cycle engine which is reduced in engine height, lightweight and compact and capable of reliably achieving exhaust emission control. To this end, the upper edge (14a) of a pilot air port (14) formed in the inner wall of a cylinder (10) is approximately level with the upper edge (15a) of an inlet port (15). At the lower end of a piston (30) opposed to the pilot air port (14), extensions (32) are provided which extend downward beyond the piston lower edge (31) opposed to the inlet port (15). The spacing (W1) between the right and left extensions (32, 32) is greater than the outer width (W2) of a balance weight (23) on a crank shaft (20). The outer peripheral surface of the extension (32) is formed with a piston groove (34) for connecting the pilot air port (14) to a scavenging port (12) during suction stroke. Further, provided below a first scavenging flow channel (71) is a second scavenging flow channel (72) of simple construction.