Abstract: In a fuel control method data used to control the amount of the fuel supply in the previous cycle is corrected in response to the output of an O.sub.2 sensor in a current cycle, and added to or subtracted from the corrected data value as the difference between a value derived from data stored in a map based on the output of a vacuum sensor and engine rotation speed in the previous cycle and a value derived from the data stored in the map based on the output of the vacuum sensor and engine rotation speed in the current cycle. The sum or difference is used as current control data.

Abstract: In a method and a system for engine control an engine control signal is generated on the basis of a signal produced at each moment from at least one sensor for detecting the operating condition of the engine, the control signal being used for engine control. In order to attain the proper engine operating condition, data representative of the detection signal from the sensor is adjusted in advance, and data for correcting the sensor output is calculated from said adjustment value, the correction data being stored in a memory. While the engine is running, the data representative of the detection signal from the sensor is corrected by the correction data stored in the memory, and this corrected detection signal representative data is used to produce the control signal.

Abstract: An engine control system with a microcomputer is disclosed which controls the amount of fuel injection of a spark ignition engine having a fuel injection system. In each intake process of a cylinder of the engine, a regular fuel injection is effected. An acceleration fuel injection is effected only once in each interval of said regular fuel injection in the case where the task actuated in predetermined cycles regardless of the engine rotational speed decides that the engine is in an accelerated condition.

Abstract: A method of controlling the air-fuel ratio so as to be effectively maintained at a desired air-fuel ratio of .lambda.=1 is composed of a combination of an electronic map control for effecting the air-fuel ratio control on the basis of map data read out from a data map stored in ROM as air-fuel ratio control data in correspondence to various operation parameters of an engine and an O.sub.2 -feedback control for controlling the air-fuel ratio on the basis of oxygen quantity detected from the exhaust gas. Upon the occurrence of changes in the control quantity for a predetermined number of times in the course of the O.sub.2 -control, the latter is changed over to the map control. At that time point, a control quantity for the map control is corrected on the basis of a mean control quantity during the O.sub.2 -feedback control. Unless a significant variation takes place in the engine operating conditions, the map control is continued for a predetermined time and then changed over to the O.sub.2 -control.

Abstract: A signal corresponding to the oxygen concentration in exhaust gas as detected by an O.sub.2 sensor is applied to a control logic circuit after analog conversion. The duty ratio of a pulse signal for keeping the optimum air-fuel ratio corresponding to a running state of an automobile is calculated by the use of the detection signal and in accordance with a program stored in a ROM in advance. The control pulse having the duty ratio is used for the switching control of a solenoid valve for regulating the air-fuel ratio of a mixture.