Patent ID: 6014962
Filing Date: 2000-01-18
Classification: F02D

Abstract:
An air-fuel ratio controller for controlling an air-fuel ratio of an air-fuel mixture supplied to an engine, comprising:a fuel injection valve to inject fuel into the engine;an oxygen sensor to detect an oxygen concentration in an exhaust of the engine, anda microprocessor programmed to:calculate a basic in section amount based on a running condition of the engine;calculate a feedback correction amount based on the oxygen concentration so that the air-fuel ratio is controlled to be a predetermined air-fuel ratio;store a learning value for a high load state, the learning value being calculated for a predetermined time based on the feedback correction amount when the high load state is developed, wherein the predetermined time is a time required to converge the learning value;clamp the feedback correction amount in the high load state after the predetermined time has elapsed; andcalculate a fuel injection amount by correcting the basic injection amount with the learning amount for the high load state when the engine is in the high load state, wherein the fuel injection amount is injected from the fuel injection valve.