DE3403260

The engine speed is periodically detected at every predetermined crankshaft angles for obtaining a plurality of engine speed data whose number equals an integral multiple of the number of cylinders of an internal combustion engine. Either maximum or minimum values among the plurality of engine speed data is determined, and such operations are repeated for a duration covering all power strokes within all the cylinders, thereby obtaining a plurality of sets of engine speed data. Then the order of engine speed data giving the maximum or minimum value within each set is obtained, and majority decision is effected to determine which order of data gives the maximum or minimum most frequently throughout all the sets. The difference between the maximum and minimum values is obtained for each set, and the amount of fuel to be supplied to the engine is controlled so that the difference becomes common to all the cylinders. The fuel amount control may be effected by means of an actuator which controls the position of a spill ring of a distributor injection pump.