Andreas Stihl Ag Co. Kg

Michael Joos

Helmut Zimmermann

Stefan Leuze

Andreas Radtke

Gerhard Osburg

Axel Klimmek

Tommy Roitsch

Reinhard Friedrich

Wolfgang Luithardt

Andreas Bähner

Andreas Lingen

Hans Holderle

Helmut Schlessmann

Olaf Schmidt

Matthias Hehnke

Peter Schmidt

Jens Kern

Joachim Baumhauer

Christoph V Hiller

An internal combustion engine of a manually operated implement, having an elastic connecting duct between the engine and an air filter for vibration-decoupled bridging of a vibration gap between engine and the air filter. The elastic connecting duct has a first conduit for fuel/air mixture and a second conduit for largely fuel-free air. The first and second conduits are separate tubes having respective bores that are separated from one another over their entire lengths, the inlet of the engine is operatively connected to the air filter via the first conduit, and an air duct window of the engine is operatively connected to the air filter via the second conduit.

Internal combustion engine having an elastic connecting duct

A two-stroke engine has a cylinder with a combustion chamber that is delimited by a reciprocating piston that drives with a connecting rod a crankshaft rotatably supported in a crankcase. In predetermined positions of the piston, the crankcase is connected by at least one transfer channel to the combustion chamber. The two-stroke engine has a mixture channel for supplying a fuel/air mixture and an air channel that supplies substantially fuel-free air to the transfer channel. In order to provide a simple adjustment of the air channel to different two-stroke engines of a model range, a component in which the air channel is formed has a throttle member that is arranged at an end face of the component. The throttle member throttles the air flow through the air channel in at least one operating state of the two-stroke engine.

Two-stroke engine

A connecting piece () between a carburetor () and an inlet channel () is disposed in an internal combustion engine () of a portable handheld motor-driven work apparatus such as a motor-driven chain saw, cutoff machine, et cetera. The connecting piece () serves to compensate for relative position changes between the engine () and the carburetor (). The connecting piece () is made of elastic material and has an expansion fold () which functions to compensate for length changes. The length of the connecting piece can be changed from a pressed length (a) to an expanded length (b). The expansion fold () partitions the connecting piece () into a carburetor-end section () and into an engine-end section (). The carburetor-end section () includes a circularly-shaped flow cross section and the engine-end section () includes a circularly-shaped flow cross section at the side facing toward the expansion fold () and has a flow cross section which departs from the circular shape at the end facing toward the engine. The connecting piece () includes on the inner side grooves () which run in the longitudinal direction.

Connecting piece

A two-stroke engine () has a combustion chamber () disposed in a cylinder (). The combustion chamber () is delimited by a reciprocating piston (). The piston () drives a crankshaft () via a connecting rod () and the crankshaft () is rotatably journalled in a crankcase (). The two-stroke engine () has an intake channel () for the supply of fuel into the crankcase (), an outlet () for exhaust gases from the combustion chamber () and an air channel () for the supply of substantially fuel-free air. A throttle element () is mounted in the air channel (). At pregiven positions of the piston (), the crankcase () is connected via at least one transfer channel () to the combustion chamber (). In order to prevent air from being drawn by suction into the air channel because of leakages during idle or at low rpm, a fluid connection is provided between the air channel () downstream of the throttle element () and the crankcase () for underpressure compensation which connection is present at least partially for a position of the piston from 90&#xb0; ahead of bottom dead center to 90&#xb0; after bottom dead center. A connection between the crankcase () and the intake channel () can be provided in lieu of, or in addition to, the connection to the air channel ().

An elastic connecting piece () is mounted between a carburetor () and an inlet channel () of an internal combustion engine (). The engine () is especially an engine of a portable handheld motor-driven work apparatus such as a motor-driven chain saw, cutoff machine or the like. The connecting piece () includes a peripherally extending expansion fold () arranged between its ends in order to compensate for changes in length. The expansion fold () subdivides the connecting piece () into a carburetor-end section () and into an engine-end section (). The annular gap () of the expansion fold () can be bridged by a seal lip (). The connecting piece () includes a peripherally extending seal seat () of axial length (g) in the region of the expansion fold (). The seal lip () can be placed in seal-tight contact with the seal seat () and substantially closes the expansion fold () fluid tight to the interior space of the connecting piece ().

A connecting piece () is disposed between a carburetor () and an inlet channel () in an internal combustion engine of a portable handheld motor-driven work apparatus. The connecting piece functions to compensate for relative position changes between the engine and the carburetor (), is made of elastic material and includes an expansion fold () for compensating for changes in position. The length of the expansion fold () is changeable from a collapsed to an expanded length. The expansion fold () subdivides the connecting piece () into a carburetor-end channel section () having a circularly-shaped cross section and an engine-end channel section () having a cross section departing from the circular form at the end facing toward the engine. The connecting piece () has a constant flow cross section over its entire length when the expansion fold () is collapsed.

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Fellbach, Germany

Michael Joos