Patent ID: 8065981

Claim:
A stratified scavenging two-cycle engine, comprising: a piston; a lead air flow channel provided in the piston for causing lead air to flow from outside into an inner space of the piston, the inner space communicating with a crank chamber; a scavenging communication port provided in a side portion of the piston; and an exhaust port, a lead air port, a scavenging port, and a scavenging inflow port provided in an inner circumferential surface of a cylinder; wherein: the scavenging port and the scavenging inflow port are air-tightly connected by a scavenging passage; the scavenging communication port is formed in a position such that the scavenging communication port overlaps the scavenging inflow port when the piston is located close to a bottom dead center; the lead air flow channel is formed in a position such that an end portion at one side of the lead air flow channel overlaps the lead air port of the cylinder when the piston is located close to a top dead center; in an intake process, while the end portion at one side of the lead air flow channel overlaps the lead air port, the lead air flows into the inner space of the piston via the lead air port and the lead air flow channel; and in a scavenging process, while the scavenging communication port and the scavenging inflow port overlap, the lead air located in the inner space of the piston flows from the scavenging port into the cylinder via the scavenging communication port, the scavenging inflow port, and the scavenging passage and then an air-fuel mixture located in the crank chamber flows from the scavenging port into the cylinder via the inside of the piston, the scavenging communication port, the scavenging inflow port, and the scavenging passage.