Air/fuel ratio control system for internal combustion engine with a high degree of precision in derivation of engine driving condition dependent correction coefficient for air/fuel ratio control

摘要

An air/fuel ratio control system derives a air/fuel ratio dependent correction value for correcting a basic fuel delivery amount as a proportional-integral control value composed of a proportional component and an integral component. The proportional component is derived on the basis of an air/fuel ratio indicative signal which varies the signal level when the air/fuel ratio varies across a predetermined stoichiometric value. The integral component is derived on the basis of a basic fuel delivery amount which is derived on the basis of engine speed and an engine load.