Abstract: In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, an air-fuel ratio feedback control parameter is calculated in accordance with the output of the downstream-side air-fuel ratio sensor in an air-fuel ratio feedback control mode therefor, and an actual air-fuel ratio is adjusted in accordance with the output of the upstream-side air-fuel ratio sensor and the air-fuel ratio feedback control parameter. In this air-fuel ratio feedback control mode, a large allowable range is imposed on the air-fuel ratio feedback control parameter. In a non air-fuel ratio feed control mode for the downstream-side air-fuel ratio sensor, a small allowable range is imposed on the air-fuel ratio feedback control parameter which, in this case, is unchangeable.

Abstract: The amount of fuel injection is augmented on a hot engine start by prolonging the fuel injection time or boosting the fuel pressure. For extension of the fuel injection time, a basic fuel injection time is prolonged according to a hot start fuel increment coefficient which is obtained from a two-dimentional map based on a intake air temperature stored in a memory during an engine operation (an operating intake air temperature) and the difference between the operating intake air temperature and an intake air temperature detected on restart of the engine. In case of an apparatus for augmenting the fuel injection by boosting the fuel pressure to be supplied to a fuel injector, the control pressure to be admitted into a diaphragm chamber of a pressure regulator is switched according to a two-dimentional map providing switching and unswitching conditions in terms of the difference between the operating intake air temperature and restarting intake air temperature in relation with operating intake air temperature.

Abstract: A method of controlling fuel supply to an internal combustion engine at the start thereof. A fuel quantity to be supplied to said engine is set in dependence on a temperature of the engine when the engine is in a predetermined starting condition, and the fuel quantity thus set is corrected to an increased value by means of a correction value which varies with a rise in the rotational speed of the engine. The varying rate of the correction value is set in dependence on the engine temperature such that the set fuel quantity decreases at a first rate with a rise in the engine rotational speed when the engine temperature is higher than a predetermined value, and at a second rate smaller than the first rate with a rise in the engine rotational speed when the engine temperature is lower than the predetermined value. The set fuel quantity is corrected by means of the correction value having its varying rate set as above while the engine is in the predetermined starting condition.

Abstract: An apparatus for controlling an internal combustion engine having starter switch. The apparatus includes a control circuit for calculating a value corresponding to the amount of fuel supplied to the engine in time during which the engine is starting. The calculated value is modified in a direction decreasing the amount of fuel supplied to the engine when the interval between the time when the starter switch is turned on and the time when the engine stalls is equal to or less than a predetermined value and the interval between the time when the engine stalls and the time when the starter switch is turned on is equal to or less than a predetermined value.

Abstract: A starting fuel supply system for an internal combustion engine, comprising an electronic injection system, and processing means which, prior to stroke identification of the engine, cause fuel to be supplied to more than one injector, including the injector relative to the cylinder first reaching the ignition point subsequent to such identification, and which has already completed the induction stroke, thus enabling substantially total intake of the fuel injected into the cylinder.

Abstract: Each of fuel injectors associated with respective cylinders of an internal combustion engine is driven several times for each air-intake with narrow drive pulses during the engine at low temperature is in a starting stage.

Abstract: An air/fuel ratio control system for an internal combustion engine that compensates, the amount of fuel supplied at engine starting based on lapsed time since the engine was operated and stopped. A lapse time from the immediately previous engine stop to the subsequent engine start is determined. Based on this lapse time, an increase value of fuel to be supplied into the engine's intake air by fuel injection valves is determined. This increase value is determined according to a pre-established of fuel temperature. The fuel supply amount is corrected upon engine start on the basis of the increase value.

Abstract: A fuel at the time of start of an internal combustion engine (8) is supplied dividedly by the injection pulse signals. The injection pulse width (T.sub.ST) of the injection pulse signals is controlled in accordance with the temperature of the engine fuel chamber (9) of the internal combustion engine.

Abstract: In an internal combustion engine, warming-up fuel enrichment is carried out in accordance with the temperature of the engine coolant. This fuel enrichment is further increased in accordance with the temperature of the engine coolant at the moment when a starter is turned on.

Abstract: A fuel supply control method for an internal combustion engine in a cold state. A basic value of fuel supply quantity is corrected to an increased value by the use of a correction variable set based upon engine temperature and engine load. Intake air temperature is detected, and the correction variable is corrected by the detected intake air temperature. Preferably, the correction variable is corrected to a larger value as the detected intake air temperature is lower.

Abstract: In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, an actual air-fuel ratio is adjusted in accordance with the outputs of the upstream-side air-fuel ratio sensor and the downstream-side air-fuel ratio sensor. The adjustment of the actual air-fuel ratio by the downstream-side air-fuel ratio sensor is prohibited in accordance with a coolant temperature of the engine.

Abstract: This invention relates to a control system for feedback control of the air/fuel ratio in an internal combustion engine, which may be an automotive engine, by using an oxygen sensor to detect actual values of the air/fuel ratio from the concentrations of oxygen in the exhaust gas. The control system has the function of temporarily shifting the feedback control of air/fuel ratio to open-loop control when any of predetermined transient operating conditions of the engine is detected. To resume the temporarily interrupted feedback control at an optimum time-point, the air/fuel ratio control system includes means to detect the degree of warm-up of the engine and means to variably determine the duration of the temporary open-loop control according to the detected degree of warm-up of the engine.

Abstract: A method for controlling the amount of fuel mixture, including a first and second fuel of different volatility, to be supplied to an internal combustion engine includes calculating a base amount of fuel mixture needed to achieve a desired air to fuel ratio at a predetermined engine operating condition. Such a base amount of fuel mixture is modified as a function of the temperature of the internal combustion engine and is a function of the percentage of the first fuel.

Abstract: A fuel injection control system for an internal combustion engine including: a cold start injection valve provided inside an intake pipe for performing fuel injection on cold starts; a switch for controlling energization of the cold start injection valve; a starter drive state detector for judging if a starter is being driven; a clock for detecting, by the starter drive state detector, a change of the starter from a nonoperating state to an operating state and for counting time elapsed from the detected change; and start controller which designates a starting fuel injection when the elapsed time counted by the clock is a first predetermined period or more and which prohibits the starting fuel injection when the elapsed time is a second predetermined period or more greater than the first predetermined period.

Abstract: A method for controlling the amount of spark advance for an internal combustion engine using a fuel mixture having a first and a second fuel of different volatility and volumetric energy content. The percentage of the first fuel in the fuel mixture is sensed and a desired base spark advance is determined. The desired base spark advance is adjusted as a function of the percentage of the first fuel to achieve a desired engine operating condition.

Abstract: The invention contemplates control circuitry applicable to an internal-combustion engine having electronic fuel injection, for fuel-priming upon cranking the engine to start the same. The circuitry is operative only when there is proper fuel pressure at the injectors, and the prime is immediate and simultaneous to all injectors. The duration of the prime is an inverse function of engine temperature. Once the priming fuel has been injected, there cannot be another priming injection until lapse of a period of time following completion of cranking, thus preventing engine-flooding in the event of a quick restart of the engine.

Abstract: In a fuel injection system for an internal combustion engine, the voltage of a vehicle-mounted battery is monitored to see if the voltage is below a predetermined voltage at which a microcomputer used in an electronic control unit is disabled or malfunctions on engine start where large current is consumed by a starter motor. During engine start, asynchronous fuel injection is performed using the result of the voltage monitoring in place of normal or main fuel injection. The amount of fuel to be injected by the asynchronous fuel injection may be limited and/or the number of times of asynchronous fuel injection may be limited so as to prevent excessive fuel supply. In monitoring the battery voltage, hysteresis characteristic may be given to a reference voltage so as to avoid undesirable chattering.

Abstract: A method and apparatus for controlling an air-fuel ratio for an engine, in which a closed-loop control and an open-loop control are performed selectively in accordance with the operating condition of the engine. The closed-loop control determines an air-fuel ratio of the mixture to be supplied to a combustion chamber on the basis of the oxygen concentration within the exhaust gas. The open-loop control determines an air-fuel ratio of the mixture by modifying the air-fuel ratio determined in the closed-loop control in a manner that the former one is lean by a predetermined ratio than the latter one.

Abstract: A fuel injection control method for an internal combustion engine includes the steps of monitoring the rotating speed of the engine and the velocity of the vehicle after the engine has been started using starting fuel injection, and performing fuel injection in an ordinary manner without performing starting fuel injection in the case where either of the following conditions is met: (1) the engine rotating speed is above a predetermined rotating speed or (2) the engine rotating speed is less than the predetermined speed and the vehicle velocity is simultaneously above a predetermined velocity.

Abstract: The invention is directed to an arrangement for metering fuel to a spark-ignition internal combustion engine equipped with a fuel injection system. The fuel metering arrangement includes a control apparatus which generates injection pulses for controlling the injection valves, the pulses being generated at least in dependence upon the rotational speed of the engine. In the event of a failure of the control apparatus, control of the injection valves is switched over to injection pulses derived from the ignition system of the engine. In this arrangement, the transfer of control may be accomplished either by pulling the central plug of the control apparatus or by automatic error detection via a speed relay.

Abstract: The fuel supply amount to an engine is gradually decreased directly after engine startup from a startup fuel supply to an after-startup fuel supply.

Abstract: In an internal combustion engine, feedback control of the air-fuel ratio is carried out in accordance with the concentration of a specific composition in the exhaust gas, so that the air-fuel ratio is close to a target air-fuel ratio on the lean side with respect to the stoichimetric air-fuel ratio, the target air-fuel ratio is variable in accordance with the engine temperature.

Abstract: The invention is directed to a method and an apparatus for controlling the overrun mode of operation of an internal combustion engine, wherein instantaneous values of the relevant negative speed change of the internal combustion engine are sensed and evaluated to control the overrun mode. In this arrangement, a higher resume speed which is selected on commencement of the overrun mode and reduced to a lower speed limit after a predetermined time function, can be shifted additionally in dependence on the negative speed change. Further, to keep an internal combustion engine from stalling, the actual value of the negative speed change can be compared with a predetermined desired value; if it exceeds that value, the decision for a resume of fuel delivery can be made without delay.

Abstract: Fuel injections are sequentially effected into cylinders of a multicylinder internal combustion engine in predetermined sequence in synchronism with pulses of a predetermined crank angle position signal from engine rotational angle sensing means. If no TDC signal pulse is generated between an immediately preceding pulse and a present pulse of a cylinder-discriminating signal, a simultaneous fuel injections are effected into all the engine cylinders upon generation of the present pulse of the cylinder-discriminating signal. Preferably, the engine rotational angle sensing means is determined to be abnormal when the simultaneous fuel injections have been effected consecutively a predetermined number of times.

Abstract: A feedback air-fuel ratio control system for an internal combustion engine has an O.sub.2 -sensor for detecting the concentration of oxygen in exhaust gases of the engine, a coolant temperature sensor, and a circuit for disabling the feedback control operation at a low coolant temperature during warming-up of the engine. The feedback control system is also disabled when the engine is rapidly accelerated or decelerated, even if the engine is warming-up at coolant temperatures greater than the low coolant temperature state.

Abstract: A system for controlling the fuel injection amount in an internal combustion engine. The fuel injection amount is calculated based on the ratio of the amount of intake air measured by an air flow meter to the engine speed. The injection amount is maintained at not less than a predetermined minimum amount during the starting of the engine even if an undershoot occurs in the signal level from the air flow meter after the starter has been switched off. Thus, a sharp decrease in the engine speed is prevented, and thus engine stalling is also prevented.

Abstract: A method and apparatus for starting a cold internal combustion engine under optimum conditions. Engine r.p.m. is maintained to a desired value until either the car is started, driven, or the temperature of the engine reaches a predetermined value, whichever first occurs. During this time, the ratio between the air and fuel fed to the engine is kept at the optimum values corresponding to the prevailing engine conditions during this time.

Abstract: A backup system for an electronic fuel injection control system as for an internal combustion engine, which has the ability, when the electronic fuel injection control device fails to function normally or when there arises the possibility of inducing this failure, to control the duration of the opening of the injector's valve and consequently the volume of fuel to be injected to the extent of permitting the start of the internal combustion engine without recourse to the signal from the sensor system now out of order or the operation of the electronic control device, and thus is capable of controlling the internal combustion engine without obstructing the operation of starting, warming-up and cruising in the case of the aforementioned trouble.

Abstract: An engine control microprocessor transient interrupt system is provided wherein an engine throttle position sensor provides a throttle position input signal to a microprocessor which developes engine control output signals in response thereto. The throttle position sensor also provides an input signal to a transient detector external to the microprocessor which provides an interrupt signal to the microprocessor in response to the rate of change of throttle position exceeding a threshold. In response to the interrupt signal, the microprocessor provides a disable signal which disables the external transient detector, and then the microprocessor monitors the rate of change of engine throttle position to determine the end of the throttle position transient condition and enables the external transient detector in response to the end of the transient condition.

Abstract: A fuel supply arrangement for an internal combustion engine, including an adjusting device for adjusting supply amount of fuel to the engine, an air temperature sensor for detecting temperature of intake air, a correcting device for correctively controlling the adjusting device on the basis of an output of the air temperature sensor, a detecting device for detecting a specific engine operating condition where the output of the air temperature sensor is higher than an actual temperature of the intake air, and a restricting device for restricting corrective control of the correcting device in response to a detection output of the detecting device.

Abstract: A fuel supply control method of controlling the quantity of fuel being supplied to an internal combustion engine after cranking thereof. Upon generation of a predetermined control signal immediately after the cranking of the engine, an initial value of a fuel increment is set, which corresponds to the engine temperature. Subsequently, the set initial value is decreased at a predetermined rate upon each generation of the predetermined control signal. A quantity of fuel is set by the use of the thus decreased value of the fuel increment and supplied to the engine in synchronism with generation of the predetermined control signal. When the fuel increment has a value larger than a predetermined reference value, the value of the fuel increment is decreased at a first rate, while when it has a value smaller than the predetermined reference value, it is decreased at a second rate smaller than the first rate.

Abstract: A feedback control is effected during warming-up operation so as to adjust an actual air-fuel ratio to a target value. A sensing element is used to probe exhaust gases to detect an air-fuel ratio of a fuel-rich mixture that is required for warming up the engine. The amount of fuel injection is corrected so that the actual air-fuel ratio is adjusted to a target value displaced to the rich side from the stoichiometric ratio.

Abstract: A gas-flow measuring apparatus and method providing an accurate measurement of the gas-flow in, for example, an internal combustion engine. The quantity of the gas-flow is measured with a measuring device including a heater mounted in the gas-flow, and a temperature-responsive element mounted in proximity to the heater. The temperature-responsive element is heated by the heater and cooled by the gas-flow and thus, has a temperature which varies in accordance with the quantity of gas-flow. The temperature-responsive element provides an output signal corresponding to the temperature and thus to the quantity of gas-flow. Power is provided to the heater when the engine is operating. A processing apparatus detects the start of power being provided to the heater. The processor then counts the time from when the start is detected.

Abstract: A fuel supply control method for an internal combustion engine having exhaust gas purifying means arranged in its exhaust passage, in which a plurality of predetermined basic fuel quantity values corresponding, respectively, to different predetermined values of at least one operating parameter of the engine are selectively read out in response to detected values of the same parameter to thereby determine fuel supply quantities appropriate to operating conditions of the engine. Among the above basic fuel quantity values, those which correspond to ones of the above predetermined parameter values that are to be assumed when the engine is operating in an idling region are set at such predetermined values as to obtain an air-fuel mixture having a predetermined air-fuel ratio at which the exhaust gas purifying means can exhibit the maximum conversion efficiency.

Abstract: An internal combustion engine has an exhaust system and an oxygen sensor fitted to the exhaust system including a sensor element and an electrically powered heater for heating the sensor element. A method is disclosed for controlling the air/fuel ratio of the air-fuel mixture supplied to the engine, by, when the voltage of the power supply to the heater has dropped below a first predetermined value and thereafter has remained below a second predetermined value higher than the first predetermined value for longer than a predetermined time period, controlling the air/fuel ratio according to engine operational parameters by an open loop form of control with no account being taken of the output signal of the oxygen sensor, and otherwise controlling the air/fuel ratio according to these engine operational parameters by a closed loop form of control taking into account the output signal of the oxygen sensor so as to obtain an optimum air/fuel ratio for the engine by a feedback control process.

Abstract: An electronic control apparatus for an internal combustion engine in which a quantity of intake air fed to the engine cylinders is detected by processing an output signal produced by an air flow sensor incorporating a heat generating element and an optimal quantity of fuel corresponding to the detected intake air flow is supplied to the internal combustion engine. Arrangement is made such that the internal combustion engine can be operated with an optimal fuel supply even when the heat generating element electrically energized is not yet heated to a predetermined temperature.

Abstract: A fuel injection control apparatus which sets an opening timing of a fuel injection valve according to driving conditions of a vehicle and independently injects an amount of fuel into each of engine cylinders. To obtain the pretty mixed mixture of the fuel and air, the fuel injection control apparatus quicken the opening timing of the fuel injection valve according to the engine coolant temperature or the amount of the throttle opening.

Abstract: A fuel injection control system for an internal combustion engine having a fuel injection valve located near an intake port can control the timing of fuel injection in synchronism with engine revolution. The fuel injection control system improves fuel atomization characteristics and uniformity of air/fuel mixture entering the engine cylinders. The control system controls the fuel injection timing so that the fuel injection occurs within a valve-overlap period during which an intake valve and an exhaust valve are both open. In order to precisely control the fuel injection timing, the piston stroke of each engine cylinder is detected with reference to the crank shaft angular position.

Abstract: Fuel supply to an internal combustion engine is controlled in accordance with the operating condition of the engine. Enrichment operation after the starting of the engine is executed for a period of from the start of the engine until the actual engine temperature becomes higher than the engine temperature at the start thereof by a predetermined value.

Abstract: A back-up system for an engine coolant temperature sensor detects deviation of the output of the temperature sensor from its designed output range to produce a fault signal. In response to the fault signal, an engine control system derives the engine coolant temperature indirectly from other engine conditions. This derivation is based on two facts: (1) the amount of fuel required to start the engine is related to engine temperature, and (2) since the calorific value of a given engine is essentially constant, the rate of increase of engine temperature is related to the integrated number of engine revolutions. Thus, when the engine is to be started, engine temperature can be derived by gradually increasing the fuel supply quantity from a minimal initial value until the engine is able to start to determine the required fuel supply quantity. Thereafter, the derived temperature value can be updated as a function of total engine revolutions.

Abstract: Injection control pulses after starting the engine are multiplied by a fuel enrichment factor A.sub.1 depending on operational temperature and rotary speed of the engine. The time derivative -A/t of the enrichment factor is kept constant up to a predetermined rotary speed limit. When the speed limit is exceeded, the time derivative increases proportionally with the rotary speed increase. In this manner faster warm-up of the engine due to higher speeds influences the fuel enrichment phase.

Abstract: An electronic engine control apparatus and method for computing various engine operating parameters such as fuel injection amount on the basis of input signals from a temperature sensor which detects engine temperature, wherein the signals from the temperature sensor are read more frequently before the complete explosion (i.e., running without a starter motor) of the engine than after attainment of complete explosion (i.e., after a start period) so that degradation of accuracy in the computed fuel injection amount, due to variation of the input signals from the temperature sensor which is caused by the starting motor, is reduced.

Abstract: In an internal-combustion engine, when the rotational speed of the engine is lower than a predetermined value, the amount of fuel to be injected into the engine is determined by the coolant temperature thereof. The amount of fuel is also changed in accordance with the change of the opening of a throttle valve provided in an intake-air passage of the engine.

Abstract: A fuel supply control system for an internal combustion engine has first and second step motor drivers for driving a step motor operatively coupled to a fuel supply control means such as a throttle valve. An initial step position setting memory stores an initial preset step position of the step motor, and a target step memory stores a target step position of the step motor dependent on an accelerator pedal position. A driver selector selects the first step motor driver for driving the step motor to the initial preset step position in response to a signal from a power-on detector, and selects the second step motor driver for driving the step motor to the target step position in response to a signal from an engine self-operation detector.

Abstract: The basic fuel injection time duration or the basic injector opening time is computed on the basis of an intake pressure and an engine speed. A start temperature correction value is selected on the basis of the engine temperature at the time of or immediately after the start up of the engine and attenuated in accordance with the time elapsed after the start up of the engine, such that, the lower the engine temperature is at the time of start up, the greater the start temperature correction value is. The rate of fuel injection rate is controlled by correcting the basic fuel injection time on the basis of the start temperature correction value and a condition of the engine.

Abstract: Method and apparatus for determining an injection moment during a start process of the internal combustion engine, in which the time point of controlling of the injection valve is shifted for a period of time depending upon the number of revolutions of the crank shaft so that the electromagnetically actuated injection valve is controlled when the battery voltage reaches the maximum value.

Abstract: A fuel supply control method for electronically controlling the quantity of fuel being supplied to an internal combustion engine at the start of the engine, in response to values of engine control parameters including at least the engine temperature. When there is an abnormality in an engine temperature detecting means that detects the value of the engine temperature, while the engine is operating in a predetermined starting operating condition, control is effected by gradually increasing the quantity of fuel being supplied to the engine with the progress of time starting from a time the engine starter is switched on, by the use of a predetermined dummy signal indicative of engine temperature, in place of an output signal from the aforementioned engine temperature detecting means. Preferably, the value of the above dummy signal is set so as to change from a higher engine temperature value to lower engine temperature values in a successive and stepwise manner at an interval of a predetermined period of time.

Abstract: In a method of and system for lean-controlling an air-fuel ratio in an electronically controlled engine, wherein the air-fuel ratio is feedback-controlled to the lean side from the stoichiometric air-fuel ratio in accordance with an output from a lean sensor generating an output signal substantially proportional to the concentration of oxygen in the exhaust gas, when it is necessary to vary a target air-fuel ratio, a target control value of an output from the lean sensor is corrected in accordance with the required variation value and the air-fuel ratio is feedback-controlled whereby the output from the lean sensor can become the corrected target control value, so that satisfactory feedback control of the air-fuel ratio can be effected even when the target air-fuel ratio is varied to a value other than the normal value.

Abstract: In a method of controlling the restart of an engine wherein the fuel amount is increased to prevent a restart failure of the engine from occurring at the time of the restart at high temperature, a fuel pressure is raised, a fuel amount is increased, an idling speed is raised and an idle ignition timing is advanced when the temperature of the engine is higher than a preset temperature and it is within a preset time period after the start of the engine, whereby the fuel consumption performance and the idling stabilizing performance are improved.

Abstract: A method for electronically controlling the air/fuel ratio of a mixture being supplied to an internal combustion engine for use in a vehicle, in response to operating conditions of the engine. A plurality of different operating regions of the engine are set beforehand, which are each defined by predetermined values of first and second parameters indicative of operating conditions of the engine. Detection is made of values of the above first and second parameters and the speed of the vehicle. At least one mixture-leaning operating region is selected from the above different predetermined operating regions, in dependence on a detected value of the vehicle speed. When it is determined from detected values of the first and second parameters that the engine is operating in the at least one mixture-leaning operating region selected, leaning of the mixture being supplied to the engine is effected.