Means and method for controlling the occurrence and the duration of time

Abstract

A control system controls the occurrence and the duration of time intervals during which sparks may be provided in the cylinders of an internal combustion engine driving a crankshaft as a function of operating parameters of the engine. Sensors sense parameters such as the vacuum in the carburetor, the position of the throttle and the torque of the crankshaft and provide corresponding signals. A distributor provides a pulse signal. Each pulse in the pulse signal has a width corresponding to a predetermined rotational displacement of the crankshaft. A counter with associated logic circuitry counts clock pulses in an up-direction during the occurrence of a pulse of the distributor pulse signal. When the counter counts down to a particular count, a decoder triggers a one shot multivibrator to provide a pulse, each pulse provided by the one shot multivibrator corresponds to the start of a spark time interval. A preset circuit receives the sensed parameter signals and presets the decoder so as to select the particular count to control the time of occurrence of the spark time intervals. A second counter is loaded with clock pulses at a reduced rate, simultaneously with the loading of the first counter. During the unloading of the first counter, the second counter is inactive. However the second counter is then unloaded at a faster rate when the spark time interval is started. Upon reaching a zero count, a spark time interval is terminated. An ignition system provides sparks to cylinders during each spark time interval.