Ignition circuit having RPM limitation for an internal combustion engine

The invention is directed to an ignition circuit for a two-stroke engine in a portable handheld work apparatus. A spark plug (2) is connected via a switch (14) to a voltage source (16). The ignition switch (14) is actuated by an electronic control circuit (15) which closes the ignition switch (14) i...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: GEYER KLAUS, SCHIEBER EBERHARD
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:The invention is directed to an ignition circuit for a two-stroke engine in a portable handheld work apparatus. A spark plug (2) is connected via a switch (14) to a voltage source (16). The ignition switch (14) is actuated by an electronic control circuit (15) which closes the ignition switch (14) in dependence upon the crankshaft angle and additional operating parameters such as the rpm of the engine (1) in order to trigger an ignition spark per revolution of the crankshaft (10). To limit rpm, the ignition switch (14) is held open when a pregiven end rpm is exceeded in order to suppress an ignition spark over at least one crankshaft revolution. In order to prevent that additional vibrations are excited by the limiting of rpm, the ignition switch (14) is closed after an end rpm is exceeded in accordance with the random principle and in dependence upon the position of the crankshaft (10) in such a manner that an ignition spark, which corresponds to a crankshaft revolution, is triggered in accordance with the random principle.