The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 2005
Filed:
May. 25, 2004
Klaus Geyer, Sulzbach, DE;
Eberhard Schieber, Backnang, DE;
Klaus Geyer, Sulzbach, DE;
Eberhard Schieber, Backnang, DE;
Andreas Stihl AG & Co. KG, Waiblingen, DE;
Abstract
The invention is directed to an ignition circuit for a two-stroke engine in a portable handheld work apparatus. A spark plug () is connected via a switch () to a voltage source (). The ignition switch () is actuated by an electronic control circuit () which closes the ignition switch () in dependence upon the crankshaft angle and additional operating parameters such as the rpm of the engine () in order to trigger an ignition spark per revolution of the crankshaft (). To limit rpm, the ignition switch () 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 () is closed after an end rpm is exceeded in accordance with the random principle and in dependence upon the position of the crankshaft () in such a manner that an ignition spark, which corresponds to a crankshaft revolution, is triggered in accordance with the random principle.