Andreas Stihl Ag Co. Kg

Bernd Engel

Michael Grether

Lukas Zürcher

Robert Koehli

Richard Wirt

A two-stroke engine possesses a cylinder, in the cylinder bore of which a combustion chamber is formed. The combustion chamber is bounded by a reciprocating piston, which drives a crankshaft rotatably mounted in a crankcase. A crankcase interior is fluidically connected to the combustion chamber across at least one transfer channel in at least one position of the piston. The at least one transfer channel emerges with a discharge opening in the crankcase interior and with at least one transfer window on the cylinder bore. It is proposed that all transfer channels have an average length as measured from the discharge opening to the transfer window, the average length being at least 1.5 in relation to the stroke, and that the volume of the crankcase interior including all transfer channels is at most 3.1 in relation to the piston displacement.

Two-stroke engine

A carburetor has a carburetor body wherein an intake channel is formed. A throttle flap is pivotably mounted by a throttle shaft in the carburetor body for controlling the free flow cross-section of the intake channel. The intake channel has a first longitudinal center axis in the region of the throttle shaft. The throttle flap has first and second end positions, wherein the throttle flap opens a larger flow cross-section of the intake channel in the second end position than in the first end position. A partition wall section, on which the throttle flap lies in the second end position, is arranged upstream of the throttle shaft. A choke flap is upstream of the partition wall section and is pivotable between first and second end positions. In their second end positions, the throttle flap and the choke flap overlap in the direction of the first longitudinal center axis.

Carburetor and two-stroke engine with a carburetor

A motor chain saw has a first driven sprocket wheel driving a saw chain lubricated via a supply pump driven by first and second drive wheel, wherein the second drive wheel is connected to the first sprocket wheel. A drive element with coupling section is connected to the first sprocket wheel and the second drive wheel is formed on the drive element. A second sprocket wheel can be used in place of the first sprocket wheel. The first and second sprocket wheels have different geometries. The coupling section has first and second followers correlated with follower surfaces of the first and second sprocket wheels. The coupling section contacts with first followers the follower surfaces of the first sprocket wheel or with second followers the follower surfaces of the second sprocket wheel when used in place of the first sprocket wheel.

Motor chain saw with supply pump

A two-stroke engine () includes a combustion chamber () which is defined by a piston () which is mounted in the cylinder () to reciprocate. The piston () has a first control surface () which controls an outlet () out of the combustion chamber () and two second control surfaces () for the transfer windows () of at least one transfer channel (). At least two transfer windows () are arranged on opposite sides of the cylinder bore (). At least a first recess is provided on the piston skirt () which extends in the peripheral area between the two second control surfaces () and which is separated from the transfer window () via a section of the piston skirt () in every position of the piston ().

A coupling device actuated by centrifugal force has a holder and at least one flyweight supported on the holder so as to be moveable in a radial direction relative to an axis of rotation about which the coupling device is rotatable. The flyweight is movable between an inner radial position and an outer radial position. At least one spring acting on the flyweight is provided that forces the flyweight into the inner radial position. At least one securing element secures at least one component of the coupling device in an axial direction of the axis of rotation. The securing element is monolithically formed on the flyweight.

Growing community of inventors

Stuttgart, Germany

Bernd Engel