Abstract: An internal combustion engine control apparatus which infers opening and closing of a throttle valve upon failure of throttle detecting switch. A programmed computer calculates basic fuel injection amount in accordance with detected rotational speed and air flow and discriminates failure of the throttle detecting switch when output of the throttle detecting switch does not correspond to the calculated basic fuel injection amount and the detected rotational speed. When the computer discriminates failure of the switch, the computer infers opening and closing of the throttle valve by comparing the calculated basic fuel injection amount with a reference value indicative of normal fuel injection amount closed throttle. The reference value is a function of the rotational speed and updated by the calculated basic fuel injection amount under closed throttle condition.

Abstract: In an electronic fuel injection control device for an internal combustion engine, an A-D converter is provided to convert an analogue signal indicative of a physical value such as an intake manifold negative pressure or an amount of suction air to a digital value, and a computer is programmed to calculate an average of a plurality of the digital values successively converted during one rotation of the engine, to determine whether or not a difference between the preceding average of the digital signals and the following average of the digital signals is larger than a predetermined value indicative of a transient operation of the engine, if so determine a first optimum physical value based on an average of at least two digital values most newly converted during one rotation of the engine, and if not determine a second optimum physical value based on the average of the digital values, and to determine an optimum fuel injection time based on one of the first and second optimum physical values and in relation to r

Abstract: In a fuel supply apparatus for an internal combustion engine, asynchronous fuel supply or injection is effected in addition to synchronous fuel injection so as to increase fuel amount on acceleration. In order to reduce time lag for supplying additional fuel, the opening degree and opening speed of a throttle valve of the engine are detected, and additional fuel supply by way of asynchronous fuel injection is effected whenever it is determined that the state of the throttle valve represents a state where fuel increase is required. Asynchronous fuel supply is then stopped when the opening degree of the throttle valve reaches an upper limit determined by the detected opening speed of the throttle valve, thereby avoiding application of excessively rich mixture.

Abstract: An apparatus for controlling an idle speed of an internal combustion engine comprises an oxygen sensor disposed in a flow of an exhaust gas from the engine for detecting a concentration of residual oxygen in the exhaust gas, valves for varying an air-fuel ratio of a mixture to be supplied to the engine, a sensor for sensing a condition of the engine, an electronic control circuit for setting a desired air-fuel ratio and for feedback controlling the valves to make the air-fuel ratio closer to the desired air-fuel ratio on response to the signal from the oxygen sensor and for deciding whether or not the feedback control is to be executed, a sensor for detecting an idle condition of the engine, control valves for adjusting a flow rate of the mixture, and an actuator for driving the valves according to the electronic control circuit when the sensor detects the idle condition of the engine. According to the apparatus, when the feedback control is interrupted, the idle speed of the engine is lowered.

Abstract: In an air-fuel ratio feedback control system for an engine having an air-fuel ratio sensor, operativeness/inoperativeness of the air-fuel ratio sensor is discriminated. An output signal of the air-fuel ratio sensor is compared and a difference thereof from a reference level is integrated for a predetermined internal of time. Integration value is compared with a discrimination reference so that a feedback control is disabled when the integration value does not attain the discrimination reference indicating inoperativeness of the air-fuel ratio sensor.

Abstract: Apparatus for controlling the operating state of an internal combustion engine (M1), has a demand amount detecting an unit (M2) for detecting amount of demand to the engine, an operating condition varying unit (M3) for varying a condition of operation of the engine, an operating state detecting an unit (M4) for detecting operating state of the engine, a target value setting unit (M5) for determining target values of variables of the operating condition, a control unit (M6) for controlling the operating condition varying unit (M3) by determining feedback amount of the operating condition variables so that detected values equal to the target values.

Abstract: An intake pipe of an internal combustion engine is formed with an air passageway so as to bypass a throttle valve portion and an air control valve to control the amount of the air flowing through this passageway is provided for this air passageway. This control valve is constituted so as to drive an actuator in accordance with the amount of an exciting current and thereby to control the amount of the air which flows through this passageway. An exciting coil of this control valve is heated and controlled by the cooling water of the internal combustion engine. When the internal combustion engine is in the idle operation state and also in the feedback control state, the temperature of the cooling water is detected. In the case where this temperature falls within a specified range, a correction value of a control amount for feedback control to allow the present rotating speed of the internal combustion engine to approach the idle objective rotating speed is calculated and stored.

Abstract: A method of controlling an internal combustion engine in which the pressure in a cylinder or working chamber of the engine is detected by reading the output signal which is delivered from a pressure sensor when a predetermined time has elapsed from a point of time when the pressure should be detected. Based on this pressure detection, the fuel supply amount or ignition spark timing is controlled.

Abstract: An air-fuel ratio control system applicable to engines having exhaust gas recirculation (EGR). A basic amount of fuel to be injected is determined on the basis of an intake air pressure or a throttle opening. When the operating condition of an engine meets a predetermined condition for an exhaust gas recirculation control mode, a correction coefficient for the exhaust gas recirculation control mode is read from map data stored in memory means to correct the basic amount therewith. Immediately after the correction coefficient has been changed, the basic amount is corrected with a correction coefficient related to the values of the correction coefficient immediately before and after it is changed.

Abstract: An intake air amount control apparatus of an internal combustion engine controls an air control valve provided at a by-path formed with respect to a throttle valve which is provided in an intake air path of the engine. When the open-loop control mode of the engine is set, the apparatus determines which of the feedback loop and the open-loop control mode has been performed. When it is found that the feedback loop control mode has been switched to the open-loop control mode, a control amount corresponding to a current cooling water temperature of the engine is read out from a preset map, thus preparing for the following open-loop control. Simultaneously, a control amount in the previous feedback control mode is read out, and a current open-loop control amount is calculated by adding a compensation value to the thus read-out control amount. When it is determined that the open-loop control mode is continuously performed, a control amount corresponding to the current cooling water temperature is read from the map.

Abstract: A closed-loop mixture control system for an internal combustion engine comprises an intake air pressure sensor, an engine speed sensor, an exhaust gas sensor for detecting the concentration of a predetermined composition of exhaust emissions from said engine, said concentration varying as a function of the air-fuel ratio of a mixture supplied to the engine, a memory having a plurality of storage locations, and a data processor. The processor derives a basic quantity of fuel to be injected to the engine as a function of the detected pressure and engine speed, a mixture trimming value as a function of the detected concentration, a fuel injection trimming value dependent on the mixture trimming value, and stores the fuel injection trimming value into a memory location exclusively addressable as a function of the detected engine speed.

Abstract: In an air flow control apparatus for controlling an amount of air flow under control of a throttle valve in an engine, a sensor produces a first signal indicative of engine operation, and another sensor produces a second signal indicative of the atmospheric pressure. A microcomputer determines whether or not the first signal indicates an idling condition of the engine. If so, the microcomputer calculates, in dependence upon the first signal, a first parameter indicative of an amount of the air flow necessary for maintaining a desired idling condition of the engine. If not, the microcomputer calculates, in dependence upon the first signal, a second parameter indicative of an amount of the air flow related to loaded condition of the engine.

Abstract: A method and an apparatus for preventing pulsations of an A/D conversion period caused when a signal indicative of an operating condition of an internal combustion engine is subjected to the A/D conversion. The A/D conversion period is provisionally determined in accordance with the number of cylinders and speed of the engine or the number of cylinders and crank angle of the engine. Two successive A/D converted values resulting from the A/D conversion operations are compared and the next A/D conversion period is corrected in accordance with the resulting difference and the engine speed. This correcting operation is repeated to control the conversion period such that the A/D conversion is always effected at the center of the pulsations.

Abstract: Idling speed of the internal combustion engine is controlled to a predetermined engine speed by correcting an engine operating parameter, such as, an ignition timing, the quantity of fuel injection, etc., to suppress a variation rate of the engine torque. Instead of detecting the torque variation rate directly, an engine speed variation rate is detected, and a correction value of the engine parameter is determined as a function of the engine speed variation rate based on the finding that the torque variation rate can be approximated as the engine speed variation rate with a fixed phase difference therebetween. Since the phase difference is determined by the engine speed, a correction value at the present moment is obtained from the previously obtained correction value which is preceding by the phase difference.

Abstract: In accordance with an amount of a change or a proportion of the change of at least one of operating parameters, such as a crankshaft rotational speed, an intake pipe pressure, etc., of an internal combustion engine equipped with an electronically controlled fuel injection system, or a rate of incremental change of the amount of the change or the proportion of the change and in dependence on whether air-fuel ratio feedback compensation by the use of an oxygen sensor is effected or not, at least one of control variables, such as a fuel injection quantity, ignition timing, etc., is corrected to ensure stable control of the rotational speed of the engine during its idling and low speed operations.

Abstract: In a method and an apparatus for controlling a quantity of fuel supplied to an internal combustion engine equipped with an electrically controlled fuel or air supply system, an amount of change of at least one controlling factor indicative of load conditions of the engine and a change in the predetermined amount of the change of the controlling factors obtained at sampling intervals are used to obtain data for correcting the controlling factors for controlling the quantity of fuel supplied to the engine, and the correction data is used to supply fuel to each engine cylinder without a delay with respect to a change in air supply to the cylinders even in a transitional state, thereby to attain accurate control of the engine.

Abstract: A method for controlling an internal combustion engine by controlling the amount of the fuel injection and the ignition timing of the engine using the output signal of a computer which takes the signals produced by the air intake pressure sensor and the rotational speed sensor, calculates the air intake pressure difference .DELTA.Pm between the preceding and the present time unit and the rotational speed difference .DELTA.N between the preceding and the present time unit, calculates the correction value from the calculated .DELTA.Pm and .DELTA.N, and modifies the control value for the engine.

Abstract: In an electronic digital control system for engine, a throttle position is sensed at predetermined time intervals to detect a variation thereof from the previous time to the present time, and, after modifying the detected variation by a correction coefficient related to a cooling water temperature to obtain the modified variation, the previous value of a fuel injection amount correction factor computed at the time of previous computation is added to the value of the modified variation to compute the sum. Then, a predetermined subtraction constant is subtracted from the sum to compute the difference therebetween, thereby obtaining the new data of the fuel injection amount correction factor, and this new factor is used to correct the basic fuel amount computed separately on the basis of the operating condition of the engine.

Abstract: A control method for an internal combustion engine equipped with an electronically controlled fuel injection system in which at least one of the control variables of the engine is corrected in accordance with engine speed and intake pressure. The amounts of change in speed and pressure are computed at intervals of a given period, and a basic control variable value is corrected in accordance with the amounts of the change. Under specific operating conditions of the engine including the start of the engine, the correction process is inhibited.