Patent attributes
A two-stroke internal combustion engine (1) includes one pair or two pairs of scavenging passageways (31, 32) of reverse flow system where scavenging outlet ports (31b, 32b) are opened to the cylinder bore (10a); the internal combustion engine being characterized in that an external air inlet port (42, 44, 46) for introducing external air into a combustion actuating chamber (15) formed over a piston (20) is formed at a portion of the cylinder (10) which is located closer to an exhaust port than a scavenging outlet port (31b, 32b) from which an air-fuel mixture (M) is introduced into the combustion actuating chamber (15) in a descending stroke of piston, and/or the external air inlet port (42, 44, 46) is formed at a portion of the cylinder (10) which enables the external air to be introduced into the combustion actuating chamber (15) prior to introduction of the air-fuel mixture (M).
