Fuel injection control method for a multi-cylinder internal combustion engine, having a fail safe function for abnormality in cylinder- discriminating means

摘要

A fuel injection control method for injecting fuel into a plurality of cylinders of an internal combustion engine in predetermined sequence starting from a fuel injection into a particular one of the cylinders, in synchronism with generation of pulses from crank angle position-detecting means indicative of predetermined crank angle positions of the engine, wherein when one of the cylinders which corresponds to a first pulse from the crank angle position-detecting means generated immediately after generation of a pulse from cylinder- discriminating means indicative of the above particular cylinder is other from the particular cylinder, the sequence of fuel injections into the cylinders is changed so as to effect a first fuel injection into the above particular cylinder immediately after the generation of the above pulse from the cylinder-discriminating means and then effect fuel injections into the other cylinders in the above predetermined sequence. The method is adapted to perform a fail safe function in the event of occurrence of an abnormality in the cylinder-discriminating means. The number of times of the above changing of the fuel injection sequence is counted up to a predetermined value, the cylinder-discriminating means is regarded as abnormal. Then, injection of fuel into the cylinders is effected in the above predetermined sequence in synchronism with pulses from the crank angle position-detecting means alone, irrespective of generation of subsequent pulses from the cylinder-discriminating means.