Abstract: In an electronic ignition control system utilizing a microcomputer, a reference signal indicative of a crank reference position is counted to sense the rotational speed of an internal combustion engine thereby controlling the ignition timing of the engine. In the system, a reference ignition position is computed using the sensed engine rotational speed as a parameter, and this reference ignition position is corrected using a plurality of information indicative of the operating condition of the engine including the information of the engine rotational speed as parameters.

Abstract: A contactless ignition system of current interruption type for an internal combustion engine comprising at least one pulser device sensing a predetermined maximum advance position and a predetermined minimum advance position of the ignition timing to generate an output signal indicative of such advance positions. On the basis of the output signal of the pulser, a first ramp signal having a first gradient and a second ramp signal having a second gradient are produced, and a signal representing the sum of a reference signal of a constant level and the second ramp signal is compared in a comparator with the first ramp signal. When level coincidence is reached between these two signals, the comparator generates a control signal controlling the turn-on position of a semiconductor switch which controls the ignition timing, so that the duration of current supply for ignition can be maintained substantially constant throughout the rotation speed ranges of the engine.

Abstract: There is proposed an ignition apparatus for use with an internal combustion engine, including therein an ac or dc power source and an ignition coil whose primary winding together with a controllable electric switching element forms a closed circuit. The apparatus includes therein a control circuit for controlling the electric switching element, which control circuit comprising a first, second, and third signal generating means for supplying control signals to the control electrodes of the switching element in synchronism with the ignition timing of the engine. The third signal generating means detects the spark positions, i.e. angular positions of the engine shaft at which the spark plugs are to be fired, at high speeds of the engine so that the maximum advance in angular position for ignition timing can be suppressed.

Abstract: In a thyristor chopper circuit used for the control of the rotational speed of an electric motor and provided with a protective system for preventing problems caused by a commutation failure in the chopper circuit, the protective system is provided with means for detecting the occurrence of commutation failure and means for certifying the operative condition or validity of the commutation failure detecting means. The operative condition certifying means is provided with means for supplying the commutation failure detecting means with a checking signal corresponding to a signal which is applied to the commutation failure detecting means upon the occurrence of the commutation failure so that whether the protective system is in a normally operative or valid condition can be certified at any time desired.