Andreas Stihl Ag Co. Kg

David Fallscheer

Heinrich Leufen

Jörg Präger

Klaus Geyer

Rolf Walter

Michael Link

Martin Kiesner

Joerg Praeger

Steffen Bantle

Erik Ames

A method is for starting a combustion engine having a pull-rope starter. A fuel/air mixture is fed to the engine via an intake channel. The mixture is ignited by a spark plug. The combustion drives the piston downward and drives a crankshaft rotationally. The fuel system has a fuel channel opening into the intake channel. An electric fuel valve is open in its currentless state and closes a fuel channel only when an operating voltage is applied. An electronic control unit actuates the fuel valve and triggers an ignition spark and is utilized by a generator to supply energy to the control unit, the fuel valve and the ignition device. To prevent excessive enriching of the fuel/air mixture during starting, the energy, which is generated at the beginning of the rotation of the crankshaft, is used to first close the fuel valve before the control unit triggers an ignition spark.

Method for starting a combustion engine having a starter apparatus

A portable work apparatus has a combustion engine for driving a work tool. An air/fuel mixture is supplied to the engine via a carburetor which is provided with an electrical heating element for heating to a given temperature. The heating element is connected to a switch via which electrical energy, which is provided by a generator driven by the engine, is supplied. When a given temperature is exceeded, the switch interrupts the energy supply. To achieve an exact temperature control, the ohmic resistance value of the heating element is stored in a memory in dependence on the temperature. The current flowing through the heating element and the voltage drop at the heating element are measured and the instantaneous resistance of the heating element is calculated therefrom. This calculated value is compared to the value stored in the memory to open or close the switch in dependence on the comparison.

Handheld work apparatus having a control unit for an electric heating element

A handheld work apparatus has a drive motor which drives a work tool and a generator. The work apparatus has a first electrical load and a connectable second electrical load. The generator provides the electrical power for the simultaneous operation of the two loads. The work apparatus has a control unit for controlling the power supplied to the first electrical load. In order to supply approximately the same power independent of voltage fluctuations, a voltage monitoring circuit is provided which, in a first operating state, sets a first signal sequence for operating the first load and, in a second operating state, sets a different second signal sequence for operating the first load. The mean power of the first signal sequence and that of the other second signal sequence are approximately equal.

Handheld work apparatus having a control unit for operating an electric load

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Filderstadt, Germany

David Fallscheer