| 主权项 |
1. A two-stroke internal combustion engine comprising:
a cylinder bore formed in a cylinder; a piston inserted into the cylinder bore and can move reciprocatably, the piston defining a cylinder chamber in the cylinder bore; a crankshaft configured to convert a reciprocating motion of the piston into a rotary motion; a crank chamber configured to house the crankshaft and receive a gas mixture fed from an intake system; a scavenging port that is open to the cylinder chamber and opened and closed by the piston; a scavenging passage, one end of which ranges to the scavenging port and the other end of which is open to the crank chamber; and an exhaust port configured to exhaust a combustion gas in the cylinder chamber to an outside and opened and closed by the piston, wherein the scavenging passage includes a wall surface that defines an orientation direction of a main scavenging gas flow spouting from the scavenging port to the cylinder chamber, in a boundary portion between the scavenging port and the scavenging passage, a wall surface located on an opposite side of the exhaust port is composed of an inclined surface inclined in a direction further away from the exhaust port than a wall surface of a deep portion of the scavenging passage, the scavenging port includes a rear wall surface located in a portion on the opposite side of the exhaust port, and the rear wall surface continues to the inclined surface to extend in the direction away from the exhaust port and generates an incidental scavenging gas flow incidental to the main scavenging gas flow and higher in speed than the main scavenging gas flow. |
