TENDNINGSVERKSAMGORINGSKRETS FOR EN FORBRENNINGSMOTOR

摘要

Electronic signal processing circuitry for use in the ignition system of an internal combustion engine is disclosed herein. A signal generator which receives crankshaft position pulses from a sensor and produces periodic output pulses which have durations equal to a constant percentage of the period of the input sensor pulses is disclosed. The generator includes a crankshaft position sensor feeding a bistable flip-flop which controls a dual slope integrator circuit having its output coupled to a comparator with the comparator output coupled back to the reset terminal of the flip-flop. The generator produces pulses at the output of the flip-flop which have durations equal to a constant percentage of the period of the crankshaft position sensor pulses. The dual slope integrator circuit produces a periodic ramp (sawtoothed) signal which is processed by a clamping circuit and a comparator to produce an ignition dwell pulse which occurs a fixed time before the occurrence of the crankshaft position sensor pulses. An engine speed monitoring circuit also receives the periodic varying ramp signal produced by the dual slope integrator and via sampling circuitry produces an output signal related to engine speed whose magnitude is updated during each cycle of the crankshaft position pulses.