STUDY CONTROL METHOD OF AIR-FUEL RATIO IN ELECTRONICALLY CONTROLLED ENGINE

摘要

PURPOSE:To improve the controllability of air-fuel ratio, by providing a procedure to decide the change of amount in intake pipe pressure or intake air, procedure to decide continuation of feedback control and a procedure to inhibit study control. CONSTITUTION:An electronic control unit (ECU) 40 performs both feedback control of air-fuel ratio in accordance with a deviation of actual air-fuel ratio from the preset air-fuel ratio and study control by studying the deviation when the feedback control is executed. A procedure to decide whether or not the change of amount per unit time in intake pipe pressure or intake air per one revolution of an engine exceeds the preset value, a procedure to decide whether or not the feedback control is continued for over a preset time after said change of amount exceeds the preset value to again decrease below the preset value and a procedure to inhibit the study control when the feedback control is not continued for over the preset time are provided. In such way, the study control in high reliability can be performed.