STRATIFIED SCAVENGING TWO-STROKE ENGINE

摘要

A stratified scavenging two-stroke engine (1) includes: a cylinder (2); a scavenging passage (7) that has a scavenging port (71) opened to an inside of the cylinder (2), the scavenging passage (7) intercommunicating a combustion chamber (R1) and a crank chamber (R2) and being injected with a leading air from the scavenging port (71); a piston (5) inserted into the cylinder in a reciprocatable manner, the piston (5) including a recess (51) on an outer circumference thereof opposed to an inner circumference of the cylinder; and an air passage (8) provided on the inner circumference of the cylinder, the air passage (8) including an air port (81) for supplying the leading air, the air passage (8) being in communication with the scavenging passage (7) via the recess (51). The air passage (8) and the scavenging passage (7) are intercommunicated/isolated by the piston (5) in accordance with the reciprocatory movement of the piston (5), and a part of the air port (81) is opened to the combustion chamber (R1) when the piston (5) is at a bottom dead center position.