Internal combustion engine having a choke flap arranged in an air filter housing

摘要

The invention relates to a two-stroke engine in a portable handheld work apparatus. A combustion chamber (3) is formed in a cylinder (2) and the chamber is delimited by a piston (5). At least one transfer channel (14) is provided which connects the crankcase (4) to the combustion chamber (3). An air channel (22) opens into the transfer channel (14) and this channel supplies essentially fuel-free gas, preferably air. The intake channel (28) of a carburetor (8) is connected to an intake opening (45) in the housing base (41) of the air filter housing (43) upstream of a carburetor throttle flap. The intake channel (28) connects downstream of the carburetor throttle flap to an intake channel (9) to the crankcase (4). To provide an ignition-ready mixture in order to start and run up the engine, it is provided that the air channel (22) is connected to a bypass opening (25) in the housing base (41) of the air filter (42) and a common pivotable choke element (24) is assigned to the intake opening (45) as well as the bypass opening (25). The choke element (24) clears the openings (25, 45) in the operating position and closes the passthrough cross section of the bypass opening (25) in the start position whereas the passthrough cross section of the intake opening (45) is reduced to a start cross section.