Abstract: An apparatus for controlling an air-fuel ratio in internal combustion engines has an RPM sensor, a combustion composition sensor, an intake air sensor and so on. Detection signals from these sensors are fetched by a microprocessor. A RAM is arranged in the microprocessor and is continuously supplied with power. The RAM has a first memory area which is divided into a plurality of areas for storing correction data corresponding to operating states of the engine. All the correction data stored in the first memory area are added together and the sum is divided by a given constant so as to obtain an updated correction amount. This updated correction amount is stored in a second memory area. The updated correction amount in the second memory area reflects the correction data stored in the first memory area. Given correction data stored in the first memory area is read out corresponding to a given intake air flow, thereby enabling feedback control.

Abstract: A fuel injection control for an internal combustion engine having electromagnetic fuel injectors determines a basic fuel injection time width of a fuel injection pulse signal applied to the electromagnetic fuel injectors in accordance with detected conditions of engine operation parameters, stores maximum fuel injection time width values predetermined in correspondence to values of a predetermined one of the engine operation parameters, reads one of the predetermined maximum fuel injection time width values corresponding to the values of the predetermined engine operation parameter and corrects the same in accordance with the values of the other engine operation parameters, and corrects the basic fuel injection time width in accordance with the corrected predetermined maximum fuel injection time width value, thereby controlling the air-fuel ratio at a desired air-fuel ratio under every operating condition of the engine, while simultaneously preventing a misoperation of continuous fuel supply from occuring in

Abstract: An electronic control type fuel injection system in which, at the time of engine deceleration the fuel injection is stopped, and when resuming to a normal fuel injection from the fuel injection stopped condition, if the reducing rate of the engine speed is smaller than a preset value, a smaller amount of fuel than the amount of fuel injection during normal operation as if fuel injection had not been stopped is first injected and subsequently the amount of fuel to be injected is gradually increased, while when the reducing rate of the engine speed is larger than the preset value, a larger amount of fuel than the fuel injection amount during normal operation is injected.

Abstract: In an air-fuel ratio control system for an internal combustion engine, the basic fuel injection amount computed from engine parameters such as engine speed and intake air flow is corrected by using map having air-fuel ratio compensation data stored battery back-up in accordance with the engine parameters. The compensation data is read out of the map in accordance with the parameters at the time of detection of the stable combustion state of the engine. When an output of an oxygen sensor is on lean side, a predetermined amount is added to the data thus read, while when the output of the oxygen sensor is on rich side, a predetermined amount is subtracted from the data thus read, thereby renewing the stored value.

Abstract: In a closed loop control system for air/fuel ratio control of an internal combustion engine, an integration correction factor is derived from the output signal of a gas sensor indicative of the concentration of an exhaust gas component, and an engine condition correction factor is selected from a memory in which a plurality of engine condition correction factors are prestored in the form of a table. The engine condition correction factor is renewed in accordance with the variation in the value of the integration correction factor so as to perform learning control. In order to prevent each of the engine condition correction factors from assuming an undesirable value which are far deviated from its standard, a constant or variable limit value is set. The limit value may be set by calculating some typical engine condition correction factors.

Abstract: A method and an apparatus for controlling the air-fuel ratio in an internal combustion engine in which the calculation of the presumed amount of fuel attached to the wall of the intake port of the engine is effected for correcting the amount of the fuel supplied to the engine in order to compensate for the variation of the air-fuel ratio of the air-fuel mixture used in the combustion of the engine.

Abstract: A closed loop mixture control system for internal combustion engines is responsive to a signal derived from an exhaust gas sensor. The sensor signal is time-integrated in a direction depending on the level of the gas sensor output to derive a first mixture corrective setting of the control system. Second corrective settings or learning data are established for the control system in correspondence with the amount of air supplied to the engine. Each of the latter settings is varied as a function of time in a direction depending on the value of the time-varying first corrective setting relative to a reference so that the second settings are automatically updated to meet varying engine performance such as aging. One of the second corrective settings is selected in response to the detected quantity of the supplied air and multiplied by the first corrective setting to correct the basic mixture control setting of the system toward an optimum value.

Abstract: An electronically controlled fuel injection system including an air flow sensor disposed in the intake pipe of an internal combustion engine upstream of its throttle valve to detect the amount of air flow to the engine and a control unit responsive to the output signal of the air flow sensor to adjust the amount of fuel to be supplied to the engine, is further provided with a fuel enrichment circuit responsive to the output signal of the air flow sensor whereby when the amount of air flow changes in a direction to decrease, a signal commanding an increase in fuel amount which is proportional to the rate of the change is fed to the control unit. The fuel enrichment circuit has an upper limit value such that the increase in fuel amount is prevented from exceeding an amount corresponding to the upper limit value. The fuel enrichment circuit is adapted so that the amount of fuel is not increased when the rate of change of the air flow in the decreasing direction is smaller than a predetermined lower limit value.

Abstract: In a feedback control system for air/fuel ratio control of an internal combustion engine, an integration correcting amount is derived from the output signal of a gas sensor indicative of the concentration of an exhaust gas component, and an engine condition correcting amount is selected from a memory in which a plurality of engine condition correcting amounts are prestored in the form of a map. The engine condition correcting amount is renewed in accordance with the variation in the value of the integration correcting amount only within a given period of time or within an interval corresponding to a given number of rotations of the engine crankshaft from an instant of detection of the variation of the gas sensor output level. Thus, the engine condition correcting amount is renewed only when the output signal level of the gas sensor is reliable.