Patent ID: 7171942

Claim:
A control device for controlling an engine speed of an internal combustion engine of a hand-held power tool, wherein the internal combustion engine comprises an ignition control unit for controlling an ignition timing of a spark plug relative to a crank angle of a crankshaft of the internal combustion engine based on a speed of the crankshaft, wherein the internal combustion engine has a centrifugal clutch driven by the crankshaft, wherein the centrifugal clutch begins to engage when a first engine speed is surpassed and is fully engaged when a second engine speed is reached, the control device comprising: a protective control unit that is activated within an engine speed range between the first engine speed and the second engine speed; wherein the protective control unit monitors a dwell time of an actual engine speed within the engine speed range; and wherein, when a predetermined dwell time of the actual engine speed is surpassed, the protective control unit intervenes in a combustion process of the internal combustion engine such that the engine speed is corrected to a value that is outside of the engine speed range.