Patent ID: 6609510
Filing Date: 2003-08-26
Classification: F01N,F02D

Abstract:
A device for controlling an air-fuel ratio of an internal combustion engine, comprising:a fuel injection valve that injects fuel to said engine; a catalytic converter disposed in an exhaust pipe of said engine; an intake air quantity detector that detects an intake air quantity of said engine; an oxygen sensor that detects an oxygen concentration in the exhaust gas of said engine; a transient operation detection unit that detects a transient operation condition of said engine; an intake air quantity correction unit that corrects the intake air quantity detected by said intake air quantity detector based on said transient operation condition; a stored oxygen quantity estimation unit that estimates an oxygen quantity stored in said catalytic converter based on the intake air quantity corrected based an said transient operation condition and on said oxygen concentration, and an injection quantity control unit that controls a fuel injection quantity by said fuel injection valve based on said stored oxygen quantity.