STRATIFIED SCAVENGING TWO-STROKE ENGINE

摘要

A stratified scavenging two-stroke engine includes: a crankcase (2); a cylinder (3) being provided with a cylinder bore (31); an intake passage (4) supplying air-fuel mixture into the crankcase (2) via an intake port (4A); a scavenging passage (5) supplying the air-fuel mixture from the crankcase (2) into the cylinder bore (31) via a scavenging port (5A); a leading-air passage (6) supplying leading air into the scavenging passage (5); and an exhaust passage (7) being disposed on an opposite side of the intake passage (4) with the cylinder bore (31) interposed therebetween, the exhaust passage (7) discharging exhaust gas via an exhaust port, in which the scavenging passage (5) includes a main passage (51) provided near the exhaust port and a sub passage (52) provided near the intake port (4A), the main passage (51) and the sub passage (52) are isolated from each other by a partition (25, 34) that extends over substantially an entire length of the main passage (51) and the sub passage (52), the sub passage (52) includes an air-fuel mixture inlet (55) provided at a position corresponding to an opening end (35) of the cylinder bore (31) that faces the crankcase (2), and the inlet (55) functions as a flow rate adjuster having a throttle effect.