Patent ID: 7243622

Claim:
A two-stroke internal combustion engine comprising: a cylinder having a bore, the cylinder including a combustion chamber, an intake port, and an exhaust port; a first scavenging passageway having a first scavenging inlet port, and a first scavenging outlet port, the first scavenging outlet port being open to the bore of the cylinder; a second scavenging passageway having a second scavenging inlet port, and a second scavenging outlet port, the second scavenging outlet port being open to the bore of the cylinder; and an external air inlet port for introducing external air into the combustion chamber; wherein: the external air inlet port is in a portion of the cylinder located at a distance from the exhaust port which is smaller than a distance from the second scavenging outlet port to the exhaust port; the second scavenging outlet port is adapted to introduce an air-fuel mixture into the combustion chamber during a descending stroke of the piston; and the first scavenging passageway and the second scavenging passageway are approximately adjacent to each other.