TWO-CYCLE ENGINE HAVING STEPPED PISTON

摘要

PROBLEM TO BE SOLVED: To provide a two-cycle engine having a stepped piston capable of effectively preventing a blow-by phenomenon of mixture even with a simple and inexpensive constitution. SOLUTION: A two-step piston 10 having a small diameter part 10a and a large diameter part 10b is fitted to a two-step cylinder 1 having a small diameter part 1a and a large diameter part 1b, so as to form an annular subsidiary chamber 11 between the cylinder 1 and the small diameter part 10a of the piston 10. This engine is provided with a mixture passage 21 introducing mixture to a crank chamber 29; an air passage 24 introducing air into a subsidiary chamber 11; a scavenging passage 30 supplying the mixture in the crank chamber 29 to a combustion chamber 2; and injection passages 70, 70A injecting the air in the subsidiary chamber 11 to the combustion chamber 2. COPYRIGHT: (C)2004,JPO