2 CYCLE INTERNAL COMBUSTION ENGINE

Japanese Patent JP3530694

B2

PROBLEM TO BE SOLVED: To prevent non-evaporative raw fuel from being led to flow into the inner circumferential surface of a crank chamber regardless of the change of the attitude of an engine, by projecting a rib-shaped projection part so as to be placed in the inside of an intake opening, to a position on the free end part side of a reed valve in the downstream side end surface of an insulator for insulating heat, which is attached to a crank case.
SOLUTION: In the case that a 2 cycle internal combustion engine is mounted in a chain saw, when operation is executed by downwardly directing the front part of the chain, saw, non-evaporative raw fuel stuck on the inner circumferential surface 22A and so on of a crank chamber gets over weirs 23 and is accumulated in a corner step difference part P. After that, when the front part of the chain saw is upwardly directed, a part of accumulated non-evaporative raw fuel tries to flow into the inner circumferential surface 22A, however, a part thereof is dammed out by a rib-shaped projection part 45 projected to a part on the free end part 36b side of a reed valve 35. Then, an air-fuel mixture from a carburetor 30 is collided with the rib-shaped projection part 45 when the reed valve 35 is started to be opened, therefore accumulated non-evaporative raw fuel is dispersed into the air-fuel mixture so as to accelerate the evaporation of the raw fuel.

JP2007320004

PORTABLE WORK MACHINE

Sasaki, Kazunori
Tajima, Katsuya

JP32708796A

May 24, 2004

December 06, 1996

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KIORITZ CORP

B27B17/00; F02B25/16; F02B33/28; F02B33/30; F02M29/00; F02M29/04; F02B63/02; F02B75/02; (IPC1-7): F02M29/00; B27B17/00; F02B25/16

平木 祐輔 （外１名）

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