Patent ID: 6857402
Filing Date: 2005-02-22
Classification: F02B,F02M,Y02T

Abstract:
1. A two-stroke engine including an engine for a portable handheld work apparatus including motor-driven chain saws, cutoff machines, the two-stroke engine comprising: a cylinder; a piston mounted in said cylinder to undergo a reciprocating movement; said cylinder and said piston conjointly defining a combustion chamber; a crankcase connected to said cylinder; a crankshaft rotatably journalled in said crankcase; a connecting rod connecting said piston to said crankshaft to permit said piston to drive said crankshaft in rotation as said piston reciprocates in said cylinder; a plurality of transfer channels fluidly connecting said crankcase to said combustion chamber at pregiven positions of said piston; said transfer channels opening into said crankcase with respective channel openings; an air filter and a carburetor; an intake channel for supplying an air/fuel mixture through an inlet into said crankcase; said intake channel being connected to said air filter and said carburetor defining a segment of said intake channel; an air channel extending from said air filter to supply essentially fuel-free combustion air to at least one of said transfer channels; said intake channel having a first length (a) measured from said air filter to said inlet; a clean air path having a second length (b) which is a mean channel length from said air filter to the channel opening of one of said transfer channels into said crankcase; and, said first length (a) being up to 60% of said second length (b).