Electronic ignition device

Abstract

An electronic ignition device for use with an internal combustion engine is coupled between an ignition coil switch and a magnetic pick-up. The pick-up produces a cyclical signal A which is integrated and applied to a first comparator, the other input of which receives a threshold. The comparator output actuates the ignition coil switch. A logic circuit combines the output Z of a zero detector receiving the cyclical signal A with the output of the first comparator. The logic circuit output is integrated to provide a signal R indicative of actual ignition displacement, and which is compared with a signal RS representing the required ignition displacement. In a first embodiment this comparison takes place in a second comparator the output of which is fed back to constitute the threshold input of the first comparator. In a second embodiment the threshold for the first comparator is defined by RS, the signals R and I being combined before application to the first comparator. By means of such control loop variations due to manufacturing tolerances, etc, will not adversely affect spark retardation.

Dependencies are inferred from the claim text.