Yamabiko Corporation

Tetsuya Isogai

Ken Shirai

Shiro Yamaguchi

Hisato Onodera

Koichirou Ogura

Among multiple scavenging passagesincluded in a cylinder, a scavenging passage connected to at least one scavenging portconstitutes a variable scavenging passage(). An upper end portion of the variable scavenging passage() has a guide surfacedefining a discharge direction of a scavenging gas discharged from a variable scavenging port() connected thereto on a horizontal plane. The guide surfaceincludes at least a first guide portion(H) defining a first discharge direction of the scavenging gas and a second guide portion(L) defining a second discharge direction of the scavenging gas. The discharge direction of the scavenging gas is changed from the first discharge direction to the second discharge direction on the horizontal plane by the first and second guide portions(H) and(L) in the scavenging stroke.

Two-stroke internal combustion engine

Provided is a stratified scavenging engine and a portable work machine that suppress THC sufficiently. A stratified scavenging engine includes: a cylinder having a cylinder bore; and a piston stored in the cylinder bore to be movable in a reciprocating manner. The cylinder has an intake port to intake leading air and a scavenging port to scavenge combustion gas, the intake port and the scavenging port being open to the cylinder bore. The piston has a peripheral surface including a piston groove to guide leading air from the intake port to the scavenging port, and the piston groove has a recess near the intake port.

Growing community of inventors

Tokyo, Japan

Tetsuya Isogai