Abstract: Disclosed herewith an air/fuel ratio control device for and internal combustion engine which is capable of carrying out either feedback control or open loop control. In feedback control, a signal indicating the concentration of exhaust gas components is generated and fed to a fuel supply control device. In open loop control, a fuel injection rate is determined corresponding to intake air flow rate. For switching between feedback control and open loop control, the air/fuel ratio control device is provided with a means for detecting an abnormal condition of signal, and a means operative in response to the abnormal signal to interrupt feedback control. The air/fuel ratio control device is further provided with a means for detecting stopping of the abnormal signal and for returning control operation to feedback control.

Abstract: According to the method, a plurality of sensor signals are generated related to vehicle operating parameters. Interruption signals are produced in response to certain sensor signals and cause execution of a main control program to be interrupted. Data related to the main control program are transferred to an auxiliary memory. An interruption processing program is executed in a non-interruptible state to determine the source of the interruption signal, after which an interruption program related to the received interruption signal is executed. The interruption program is interrupted in response to each additional interruption signal and data related to the interrupted interruption program is stored in an auxiliary memory. The interruption processing program is then re-executed and a FLAG is stored identifying the interruption program related to each additional interruption signal.

Abstract: A control system is disclosed which includes a digital microcomputer adapted to perform routines for controlling various operating parameters for an internal combustion engine. The system includes at least one switch adapted to detect a specified engine operating condition. Means are provided for causing the microcomputer to perform a routine required for the specified engine operating condition when the time of continuous occurrence of the specified condition exceeds a predetermined value.

Abstract: A control device for an internal combustion engine comprising a knocking detecting means and an operating and controlling means which generates a feedback control signal in response to a knocking detection signal from the knocking detecting means and which feedback controls ignition timing, etc. so as to maintain the firing condition of the engine in optimum condition. The control device further comprises an acceleration detector, the output signal of which controls the knocking detecting means or the operating and controlling means in such a manner that said feedback control signal is amplified to a greater extent in the accelerating condition than in the normal condition, as a result of which the ignition timing, etc. is feedback controlled more quickly in the accelerating condition than in the normal condition, so that the firing condition is maintained in optimum condition even in the accelerating condition.

Abstract: A control device for an internal combustion engine is disclosed in which an ignition timing, etc. is feedback-controlled according to the detected knocking state. An output signal of a knocking sensor is half-wave rectified by a signal treating section and smoothed by a smoothing section to obtain a first reference signal. The rectified signal and the smoothed signal thereof are then compared by a first comparator section and the difference signal thus obtained is integrated by an integrator section to obtain a signal substantially depending on the strength of the knocking. The first reference signal is also applied to a function generator which generates a second reference signal as a function of the first reference signal and also corresponds to the components caused by the factors other than the knocking. Finally the integrated signal and the second reference signal are compared by a second comparator section to produce a correct knocking detection signal.

Abstract: An internal combustion engine self-testing control system has a microcomputer, which includes a memory unit pre-programmed with a program for testing the microcomputer. The system is so programmed as to be able to test itself by using an indicator to show the system state before controlling actuators that affect the engine operating values. That is, since it is impossible to test the system merely by observing the indicator states produced by the system, one or more test processes are added before controlling the actual engine operating values. In one example, the test timing is controlled by a power signal generated when the power supply is turned on, a start signal is generated when a starting switch is turned on (while the engine is being cranked), and a revolution indicating signal is generated when the engine is rotating.

Abstract: A system for controlling in a feedback control mode the air-fuel ratio of an air-fuel mixture to be supplied to an internal combustion engine in response to the deviation from a reference value, of an output of an exhaust sensor for sensing the concentration of a component of engine exhaust gas. The reference value is varied even during stopping of the feedback control due to an lowered engine temperature, thereby preventing an erroneous control. Additionally, the reference value and the value of a current flow to the exhaust sensor are varied immediately when the feedback control is stopped due to lowering in the engine temperature, thereby quickening the initiation of the feedback control.

Abstract: A fuel supply control system is disclosed which uses a stored program type digital computer for calculating a basic amount of fuel and modifying the basic amount in accordance with various correction factors dependent upon engine operating conditions so as to determine an actual amount of fuel supplied to an engine. The actual fuel amount is determined by adding all correction factors dependent upon engine temperature and multiplying the sum by the basic fuel amount.

Abstract: A polymer composition containing a physiologically active substance and being capable of releasing it at a controlled rate can be prepared by contacting 10 parts, by weight, of one or more polymerizable monomers and 0.1 to 30 parts, by weight, of one or more physiologically active substances and irradiating them with light or an ionizing radiation while maintaining the system in an anhydrous condition and in airless state.

Abstract: Mixture ratio control for internal combustion engines supplies a constant current into an exhaust gas sensor to develop a voltage of a substantial magnitude in proportion to the initial high value of the gas sensor internal impedance during low temperature conditions. The voltage so developed decreases as a function of time corresponding to the decrease of the internal impedance with temperature. A voltage detector is provided to trigger the control system to operate in a closed loop mode when the gas sensor voltage is reduced to a level below a first threshold level. Responsive to the output of the voltage detector the supplied current is momentarily interrupted to allow the gas sensor voltage to drop rapidly to a level which is higher or lower than a second threshold level depending on the concentration of the sensed gas in the exhaust system. A second detector senses this voltage drop relative to the second threshold to determine whether the gas sensor output represents rich or lean condition.

Abstract: An air flow rate compensation circuit is provided to compensate for an erroneous air flow rate signal produced in response to the movement of the flap of an air flow meter disposed in the intake air passage of an internal combustion engine where the erroneous nature of the signal occurs because of an overshoot characteristic of the flap. The compensation circuit produces an output signal with which either an air/fuel ratio control signal produced in response to the air flow rate signal or the air flow rate signal per se is modified where the output signal is produced in response to the movement of the throttle valve or the variation of the air flow rate signal.

Abstract: A closed loop mixture control system for an internal combustion engine comprises an exhaust gas sensor, a source of injecting a current into the exhaust gas sensor to develop a substantial voltage across the internal impedance thereof, and a variable reference setting circuit which establishes a variable reference voltage and reduces its value as a function of time such that the reference voltage lies between the maximum and minimum peak values of the output signal from the exhaust gas sensor.

Abstract: In an electronic fuel injection system for an internal combustion engine, a throttle position sensor provides an output pulse with a duration corresponding to the time interval during which throttle is nearly closed. The output from the throttle position sensor is nullified when the pulse duration is smaller than a predetermined value to prevent fuel cut-off during brief closure of throttle during transmission gear changes. The output from the throttle position sensor is used to cut off fuel only when the throttle closure time extends beyond the predetermined time interval.

Abstract: A circuit is provided in an electronic closed loop air-fuel ratio control system for starting and terminating the operation of the system at different voltages from an exhaust gas sensor.

Abstract: A fuel control system for an internal combustion engine includes an exhaust gas sensor from which feedback control signal is derived, a limiter for limiting the maximum and minimum voltages of the control signal and a triangular wave generator. The triangular wave has a constant amplitude peak of which the maximum value is slightly greater than the maximum voltage of the control signal and the minimum value is slightly below the minimum voltage of the control signal. A comparator is provided to produce an output at one of two binary levels depending upon whether the control signal is above or below the instantaneous value of the triangular wave. The output from the comparator is a train of pulses whose duty cycle ranges from predetermined minimum to maximum values which correspond respectively to the minimum open and closure times of air-fuel mixing control valves.

Abstract: The operation of an electronic closed loop air-fuel ratio control system is inhibited while exhaust gas temperature is low, and a rich air-fuel mixture is intermittently fed to an internal combustion engine in order to properly initiate the operation of the system.

Abstract: A disabling circuit for a closed loop fuel controlled internal combustion engines of the type wherein fuel is completely cut off during deceleration includes a circuit for generating an electrical signal of a duration corresponding to the duration of fueld cut-off. A timing circuit respectively insensitive and sensitive to electrical signals of short and long durations derives a disabling signal which clamps the feedback signal to a suitable control voltage until the end of the electrical signal. The timing circuit is responsive to the end of the electrical signal to introduce a delay time to prolong the disabling signal and prevent the lean mixture fuel cut-off periods from adversely affecting control system when it resumes closed loop operation.

Abstract: In a fuel mixture control system including an exhaust gas sensor located within an exhaust system of an internal combustion engine, maximum and minimum peak values of the gas sensor output are detected. A direct-current pedestal is added to the detected minimum peak value. A comparator detects when the added minimum peak exceeds the detected maximum peak value to provide a disabling signal to the mixture control system to switch its operational mode from closed loop control to open loop control when the temperature of the gas sensor falls below its operating temperature typically during prolonged idle condition.

Abstract: A closed-loop control system for an internal combustion engine comprises an exhaust composition sensor, a control unit for generating a control signal in response to the detected exhaust composition to maintain the mixture at a predetermined value, and a sensor for idling condition. The amplitude of the control signal is reduced by a predetermined amount in response to the detected idling condition so that the time required for the mixture to approach the predetermined value is thereby reduced.

Abstract: In a closed loop air fuel mixture control system in which an exhaust gas sensor is provided to control the mixture ratio, a detector is provided to detect an operating condition of the engine to change the control from the closed mode to an open control mode when the exhaust gas sensor begins to fail under the sensed operating condition.