Ignition timing control unit for a car engine and method thereof

Abstract

An ignition timing control unit for a car engine by use of a microprocessor having a CPU, A ROM, and a RAM and a plurality of sensors, each output of which is connected to the input of the microprocessor so as to detect various parameters about running conditions of the engine in which various operations and calculations, such as determining whether or not the current engine speed detected is larger than an averaged out value which was detected previously and which has been stored in the RAM, updating the old weighting averaged value stored in the RAM with a new weighting averaged value, calculating a delay angle amount to be corrected for a spark advance angle and an effective spark advance angle value, and controlling the output timing of the ignition current to be applied to the igniter are carried out in the CPU of the microprocessor, in accordance with particular control programs according to the present invention which have been stored in the ROM. With this construction, an over control of the ignition timing due to the fluctuation in the engine speed which was met in the prior art can be prevented by the averaging processing of the engine speed and a suitable ignition timing control becomes possible, thus reducing shocks and 'hiccups' which otherwise often occur at the time of the abrupt acceleration or deceleration.