Patent ID: 6401672
Filing Date: 2002-06-11
Classification: F02B,F02M,Y02T

Abstract:
An internal combustion engine including an engine in a portable handheld work apparatus, the internal combustion engine comprising:a cylinder having a cylinder wall; a piston mounted in said cylinder to undergo a reciprocating movement along a stroke path between top dead center and bottom dead center during operation of said engine; said cylinder and said piston conjointly delimiting a combustion chamber; a crankcase connected to said cylinder; a crankshaft rotatably mounted in said crankcase; a connecting rod connecting said piston to said crankshaft to permit said piston to drive said crankshaft as said piston reciprocates in said cylinder; at least one transfer channel connecting said crankcase to said combustion chamber; said transfer channel having a first end defining an entry window opening into said combustion chamber and a second end opening into said crankcase; an air channel connected to said transfer channel for supplying an essentially fuel-free gas flow thereto; a carburetor for supplying an air/fuel mixture; said carburetor having an intake channel and a carburetor throttle flap; an inlet channel downstream of said carburetor flap for conducting said air/fuel mixture into said crankcase; an air filter having an air filter housing; said air filter housing having a base wall and said base wall having an intake opening formed therein; said intake channel being connected to said intake opening upstream of said carburetor throttle flap; said base wall also having a bypass opening formed therein and said air channel being connected to said bypass opening; a common choke element provided for said intake opening and said bypass opening; and, said choke element being displaceable between an operating position wherein said intake opening and said bypass opening are clear and a start position wherein the cross section of said intake opening is reduced to a start cross section and said bypass opening is essentially closed.