Andreas Stihl Ag Co. Kg

Jochen Gantert

Gerhard Osburg

Reinhard Gerhardy

Klaus Geyer

Florian Hoche

Friedrich Hollmeier

Andreas Bähner

Michael Dietenberger

Karsten Schmidt

Frederik Herrmann

Martin Kiesner

Steffen Bantle

Andreas Baehner

Friedrich Holmeier

The invention relates to a method for adapting the composition of a mixture of fuel and combustion air. The mixture is supplied to a combustion chamber of a mixture-lubricated combustion engine in a work apparatus. The fuel is supplied to the combustion engine via a controlled fuel valve. In an operating state (I) of the combustion engine, the quantity of fuel is metered by the fuel valve. For the purpose of adapting the composition of the mixture, the combustion engine is shifted into a special operating state (II) which differs from the normal operating state (I). After starting, the combustion engine is operated in a first rotational speed range (B) for a prespecified operating time (T), wherein, after the prespecified operating time (T) has elapsed, the operating state (II) for adapting the composition of the mixture is initiated by a prespecified user action.

Method for adapting the composition of a mixture of fuel and combustion air

A carburetor has a housing with an intake channel section. A throttle element and a choke element are arranged in the intake channel section and are adjustable between a closed position in which a flow cross-section of the intake channel is substantially closed and an open position in which the flow cross-section of the intake channel is substantially released. The choke element has a start position in which the flow cross-section of the intake channel is at least partially closed. A coupling device couples the throttle element to the choke element when the choke element is in the start position. The choke element has an enriching position. The coupling device has an actuator that moves the choke element into the enriching position when the throttle element is moved, starting from the start positions of the throttle element and of the choke element, toward the open throttle position of the throttle element.

Carburetor

A carburetor arrangement for an internal combustion engine in a manually guided implement, such as a power chainsaw, a cut-off machine, etc. is provided. A regulating chamber delimited by a regulating diaphragm is provided. Upon deflection of the diaphragm due to underpressure in the regulating chamber, the latter is connected with a fuel tank. Via at least one nozzle, the regulating chamber opens into an air channel that supplies fuel/air mixture to the engine. The carburetor arrangement includes a scavenging pump that is disposed in a return line from the regulating chamber to the fuel tank, and in which is formed a pump chamber. The scavenging pump serves to completely fill the regulating chamber with fuel before start-up of the engine. To prevent the fuel/air mixture from becoming too lean after start-up, especially upon opening of the choke valve, a supply line is provided from the pump chamber into the air channel and supplies additional fuel to the air channel during the run-up phase.

Carburetor arrangement

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Urbach, Germany

Jochen Gantert