Andreas Stihl

Eberhard Scheiber

Jurgen Trost

A method of controlling ignition of an internal combustion engine as a function of engine RPM includes the steps of revolving a magnet wheel and inducing with the revolving magnet wheel in an induction coil an initial voltage. At least one delay element is provided and the delay element is switched on and off upon engine RPM. A transformed voltage is deduced from the initial voltage via the at least one delay element and the ignition is tripped when the transformed voltage surpasses a preset threshold. The device for performing the method has a magnet wheel rotating with the crankshaft of the engine and an induction coil coordinated therewith wherein an initial voltage is induced in the induction coil by the magnet wheel. A plurality of switchable RC members connected to the induction coil are provided. The switchable RC members have a first capacitor and the RC members are switched on and off depending on engine RPM. A transformed voltage is deduced from the initial voltage via the RC members and detectable at the first capacitor. A switching device, connected to the first capacitor such that the transformed voltage at the first capacitor is supplied to the switching device is provided for comparing the transformed voltage with the preset threshold and for tripping the ignition when the preset threshold is surpassed.

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Backnang, Germany

Eberhard Scheiber