STRATIFIED CHARGE TYPE TWO-CYCLE ENGINE, AND OPERATION METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To improve a two-cycle engine used as a drive prime mover in a portable manual working machine such as a chain saw, a bush cutter and a cutting polishing machine to assure complete filling for a combustion chamber using an airfuel mixture and reduce an air-fuel mixture portion leaked via an exhaust port. SOLUTION: A scavenging passage 15 is made to be located in the vicinity of the exhaust port, and the total of a structural volume between a scavenging window 25 of the passage 15 and a flow-in opening 35 of the passage 15 is made to come within about 20%-60% of total air consumption on volume measurement in the engine 1 in a nominal engine speed.