Patent ID: 7681565
Filing Date: 2010-03-23
Classification: F02D

Abstract:
1. An air/fuel ratio control system for an internal combustion engine, which has a plurality of cylinders and an air/fuel ratio sensor, wherein the air/fuel ratio sensor is disposed at an exhaust gas merging portion of an exhaust passage where exhaust gas discharged from the plurality of cylinders merges together, the air/fuel ratio control system comprising: an air/fuel ratio control means for individually controlling an air/fuel ratio of each of the plurality of cylinders based on an output of the air/fuel ratio sensor; an abnormality diagnosis means for determining whether an abnormality of responsivity of the air/fuel ratio sensor exists; and an enabling means for enabling the air/fuel ratio control means to execute the individually controlling of the air/fuel ratio of each of the plurality of cylinders when the abnormality diagnosis means determines that the abnormality of responsivity of the air/fuel ratio sensor does not exist after starting of the engine.