JPS6463636A - Air-fuel ratio control device for engine - Google Patents

Abstract

PURPOSE:To obtain exact learning correction value by normalizing each of learning correction values belonging in the same fuel injection quantity zone and the same intake quantity zone, and leveling the above-normalized values per zone to compute characteristic correction values for intake and fuel injection quantities. CONSTITUTION:In an electronic control unit (ECU) 17, a control correction value for air-fuel ratio is learned on the deviation of the air-fuel ratio from its target value at the time of air-fuel ratio feedback control during the operation of an engine 1, and the learned value is mapped per learning zone classified by an intake quantity and a fuel injection quantity for its storage. A learning correction value belonging in the same fuel injection quantity zone is normalized by dividing it by the learning correction value belonging in a reference intake quantity zone, and each normalized value is leveled per intake quantity zone to compute a characteristic correction value for intake quantity. In addition to that, each learning correction quantity belonging in the same intake quantity zone is normalized per intake quantity zone by dividing it by the learning correction quantity belonging in a reference fuel injection quantity zone, and each normalized value is leveled per fuel injection quantity zone to compute a characteristic correction value for fuel injection quantity.