ES418709A1 - Ignition system dependent upon engine speed - Google Patents

Abstract

An internal combustion engine is comprised of at least one engine cylinder, devices for introducing a combustion mixture into the cylinder, and an electrical igniting element operative for igniting the combustion mixture in the cylinder once per ignition cycle. An ignition transformer has a secondary winding connected across the igniting element, and also has a primary winding. A flow of current is established through the primary winding. An electronic switch is connected in the current path of the primary winding to control the flow of current through the primary winding. A triggering unit generates a train of crankshaft-synchronized triggering signals. A monostable control circuit has a trigger input for receipt of such triggering signals, and is operative when triggered into the unstable state for rendering and maintaining the electronic switch non-conductive for the duration of the unstable state, so as to interrupt the flow of current through the primary winding and induce across the secondary winding a voltage surge causing the igniting element to ignite the combustion mixture in the engine cylinder. When the monostable control circuit reverts to its stable state, it renders and maintains the electronic switch conductive for the duration of the stable state, whereby to establish a build-up of current flow in the primary winding in preparation for the next interruption of current flow. The monostable control circuit includes a timing stage operative for automatically increasing the ratio of the duration of the unstable state to the duration of the ignition cycle with increasing engine speed within a predetermined range of engine speeds.