| 摘要 |
PROBLEM TO BE SOLVED: To reduce exhaust amount of THC(total hydrocarbon) by avoiding blow-by of air-fuel mixture into an exhaust port, to increase air-fuel mixture density charged into a combustion chamber by raising scavenging efficiency and to raise an engine output by improving combustion, in a crankcase scavenging compression type two-cycle engine. SOLUTION: In a crankcase compression scavenging type two-cycle engine, a scavenging passage is constituted so that a blow-up angle (α) formed by an upper wall surface continuous to a scavenging port and a right angle direction line with a cylinder as a center may be different in the peripheral direction of the cylinder. When a blow-up angle at a portion close to an exhaust port and a blow-up angle at a portion close to an intake port are determined forα1 andα2, respectively, the blow-up anglesα1 andα2 are characterized by being constituted asα1<α2. |
