Patent ID: 8662047
Filing Date: 2014-03-04
Classification: F02B,F02D,F02N

Abstract:
1. A handheld work apparatus comprising: an internal combustion engine; a starter device operatively connected to said internal combustion engine; said internal combustion engine including: a cylinder defining a combustion chamber and a cylinder longitudinal axis; a crankcase connected to said cylinder; a crankshaft rotatably journalled in said crankcase; a piston disposed in said cylinder so as to move back and forth therein to drive said crankshaft and to delimit said combustion chamber; at least one transfer channel for connecting said crankcase to said combustion chamber at constructively pregiven positions of said piston; said transfer channel having at least one transfer window opening into said combustion chamber; an inlet for receiving combustion air into said crankcase; a device for metering fuel; an outlet for passing exhaust gases from said combustion chamber; said transfer window, said inlet and said outlet all being function openings of said internal combustion engine; said cylinder having an imaginary center plane which partitions said inlet at the middle thereof and contains said cylinder longitudinal axis; said piston having a piston ring arranged therein; said piston ring being configured as an open ring having two mutually adjacent ends conjointly defining a piston ring gap; said cylinder having an inner wall surface defining a cylinder bore for accommodating said piston; said function openings being disposed in said inner wall surface defining said cylinder bore; said cylinder bore further having a recess formed in said inner wall surface which bridges said piston ring in at least one position of said piston so as to establish a connection between said combustion chamber and said crankcase; said recess being at a predetermined spacing to all of said function openings in said wall surface defining said cylinder bore so as to preclude a direct connection between said recess and said function openings; and, said cylinder bore having a plurality of said recesses formed therein and each of said recesses having a flow cross section of less than 5 mm