Patent ID: 6880525
Filing Date: 2005-04-19
Classification: F02P

Abstract:
1. An ignition circuit for an internal combustion engine including a two-stroke engine in a portable handheld tool, the engine having a crankshaft and the ignition circuit comprising: a spark plug; a voltage source; an ignition switch connecting said spark plug to said voltage source; a control circuit for actuating said ignition switch and said control circuit closing said ignition switch in dependence upon the angular position of said crankshaft and other parameters of said engine to trigger an ignition spark per revolution of said crankshaft; and, said control circuit including means for closing said ignition switch after a limit rpm of said engine is exceeded with said closing above said limit rpm being in accordance with a random principle and in dependence upon the position of said crankshaft so as to cause an ignition spark, which corresponds to the crankshaft revolution, to be triggered in accordance with said random principle.