Abstract: A fuel supply control system for an internal combustion engine in which an accelerating fuel increment of fuel supplied to the engine is set in response to the detected change rate in the opening degree of the throttle valve. Further, the accelerating fuel increment is set in such a manner that it is smaller as the detected reduction gear ratio of the transmission is larger. Advantageously, the accelerating fuel increment is set to increase at a smaller rate as the above detected change increases within a region within which the change rate is smaller than a region in which the change rate is larger.

Abstract: In order to compensate for the effect of a by-pass passage which by-passes air about the engine throttle valve when a predetermined vacuum prevails downstream thereof, or the delay in air flow within the induction system in response to the demand for engine power, a target torque value is derived based on the engine speed and the accelerator pedal depression amount and this value is used in connection with one or both of the fuel supply and the air flow control. In some embodiments two basic injection pulses are developed and one is selected to suit the instant induction conditions. In other embodiments, selectively delayed target torque values are used to individually modify the throttle valve control and injection fuel supply amount.

Abstract: A pressure sensor is provided for detecting the pressure of intake air in a cylinder of an engine. A pressure difference between a first cylinder pressure detected after closing an intake valve and a second cylinder pressure after the first cylinder pressure detection and before an ignition timing. The quantity of intake air is calculated based on the pressure difference and the engine seed. A basic fuel injection pulse width in calculated based on the calculated quantity of intake air. A fuel injector is actuated in accordance with the calculated basic fuel injection pulse width for injecting fuel.

Abstract: A fuel injection control apparatus for an internal combustion engine has a controller, which includes a microprocessor for executing a predetermined processing in response to fundamental parameters representing the operational condition of the engine, produces a basic fuel injection pulse on the basis of a suction air quantity and a rotational speed of the engine and corrects the basic fuel injection pulse in accordance with the degree of acceleration or deceleration required, thereby to provide a fuel injection pulse applied to a fuel injector. The microprocessor is provided with membership functions varying with respect to acceleration or deceleration and determines a correction coefficient for correcting the basic fuel injection pulse on the basis of the degree of acceleration or deceleration required in accordance with fuzzy reasoning using the membership functions.

Abstract: A fuel injection device for an automotive spark ignition internal combustion engine provided with a supercharger is disclosed, wherein the amount of fuel injected in synchrony with the crank angle signal is determined on the basis of the intake air pressure. The increment of the air pressure data over each fuel injection period is compared with a first threshold level to determine the first augmentation. The pressure data is averaged over each fuel injection period, and the increment of the averaged pressure data over a predetermined interval of time is compared with a second threshold level to determine the second augmentation. The fundamental amount is calculated on the basis of either the instantaneous or the averaged pressure data, in dependency on the value of the first augmentation amount.

Abstract: A system for electronically controlling an engine for a vehicle is disclosed which is of the kind electrically controlling the opening of a throttle valve controlling the quantity of intake air supplied to the engine. The electronic engine control includes setting a target acceleration of the vehicle according to an amount of depression of an accelerator pedal by the driver, comparing the target acceleration with an actual acceleration of the vehicle to find an error therebetween, setting a target value of the throttle valve opening on the basis of the acceleration error, and controlling the throttle valve opening until it attains the target value.

Abstract: An apparatus for controlling an internal combustion engine having a plurality of cylinders and fuel injectors provided to inject fuel in a sequential fashion for the respective cylinders. Fuel injection is made twice from a given fuel injector. The control circuit calculates a first value for the amount of fuel injected from the fuel injector during the first fuel injection and a second value for the amount of fuel injected from the fuel injector during the second fuel injection. During transition of the engine operation, an engine load variation is produced between the times at which the first and second values are calculated. A correction factor is calculated based on the engine load variation with an estimation of a first value to be calculated for the cylinder when the fuel injected during the first and second fuel injections is charged in the cylinder.

Abstract: An air-fuel ratio control system for a two-cycle engine is disclosed, which includes a cylinder, a crank case serving also as a pressure chamber, a fuel injection unit including an injector and a pump, an engine speed detecting element for detecting the engine speed, and a throttle opening degree detecting element for detecting the opening degree of a throttle valve.

Abstract: A fuel controller for an internal combustion engine has a control unit which calculates the amount of fuel to be supplied to the engine by fuel injectors and drives the fuel injectors with a prescribed timing. The timing of the fuel injection is advanced at high engine speeds. The fuel injection timing is set such that the fuel injection is performed substantially in synchrony with the calculation of the amount of fuel to be supplied even when the fuel injection timing is advanced.

Abstract: The quantity of air induced in a cylinder of an engine is estimated by using equations based on various coefficients. The coefficients are stored in a memory and derived in accordance with engine operating conditions. The estimated quantity of induced air is corrected so as to approximate quantity of air actually induced in the cylinder. A basic injection pulse width is calculated based on the corrected air quantity. The basic injection pulse width is corrected by a feedback coefficient, thereby producing a fuel injection pulse width signal for operating a fuel injector of the engine.

Abstract: A control unit has a fuel supply controller and a throttle valve opening degree controller. The fuel supply amount controller estimates and calculates the amount of fuel being supplied in cylinders with a real time. The throttle valve opening degree controller calculates a necessary opening degree so as to give a predetermined air-fuel ratio in accordance with a result value by the fuel supply amount controller. The fuel supply amount controller has a processing in which a fuel supply amount is corrected in accordance with an increase or decrease rate of an amount of fuel being adhered to an inner wall surface of an intake pipe. The throttle valve opening degree is controlled in accordance with a value obtained from the throttle valve opening degree controller as a control target value. A time lag in a follow-up for fuel is anticipated in advance, a desirable target air-fuel ratio is maintained correctly and easily.

Abstract: An engine control apparatus in which a basic fuel injection pulse width is calculated based on various data from various sensors provided for an engine, the basic fuel injection pulse width is corrected by various factors determined based on engine conditions, and a fuel injector provided for the engine is controlled based on the corrected fuel injection pulse width, is characterized in that a period of time from a time the engine is controlled to accelerate whereby an air-fuel ratio changes into a lean state until a time the air-fuel ratio changes into a rich state is detected, and a fuel increment for the acceleration is corrected, based on the detected period of time.

Abstract: A fuel injection control system derives a correction coefficient for compensating overshooting component in measurement of an engine load indicative parameter, such as an intake air flow rate. The correction coefficient may be variable in such a manner that it increases according to increasing of the engine load. The correction coefficient may be used for correcting either the measured engine load parameter or the fuel injection amount derived taking the measured engine load.

Abstract: A fuel injector for a spark ignition internal combustion engine is disclosed, wherein the amount of injected fuel is increased by an extra amount when the engine is in a transient accelerating state. The air pressure within the air inlet passage to the engine is detected by an air pressure sensor, and the load condition is judged by comparing the detected pressure with a reference level. Further, the variation or increment of the detected pressure over each fuel injection period is calculated and compared with a high or a low threshold level selected in accordance with the load condition of the engine. Preferably, the high threshold level is selected when the high load condition continues over a predetermined length of time, the low threshold level being otherwise selected. The amount of transient extra increase is determined in accordance with the result of the comparison of the pressure variation with the selectd threshold level.

Abstract: An engine control apparatus comprises a throttle sensor, a pressure sensor for detecting a pressure in the intake manifold of an engine as a value of the absolute pressure, an engine revolution speed detector, a zone detector for detecting the fact that a signal value indicating a degree of opening of a throttle valve and a signal value indicating an engine revolution speed fall in a predetermined atmospheric pressure detection zone and a processing unit to calculate a value of atmospheric pressure by adding a set value to a signal of pressure upon detecting said values being in the detection zone. A timer may be provided to detect the fact that the signal values of the degree of opening of the throttle valve and the engine revolution speed are continuously in the atmospheric pressure detection zone for a predetermined time.

Abstract: A fuel injection control device comprising an electronic control unit in which a changing rate of the amount of air fed into the engine cylinders per one revolution of the engine is calculated. The amount of fuel injected by the fuel injector is increased and decreased when the changing rate becomes positive and negative, respectively. The decrease in the amount of fuel injected by the fuel injector is prohibited even when the changing rate becomes negative until a predetermined time has elapsed after the engine is started.

Abstract: The throttle valve position is sensed and the effective cross sectional area of the induction passage determined via table look up. The value thus derived is divided by the engine speed. A basic air induction quantity is then determined via table look up and subsequently modified using a correction coefficient to allow for the effect of engine speed on the amount of air inducted into each cylinder. The effect of injector position (viz., MPI/SPI) is taken into consideration and values suited for both generated in given embodiments. In the event that the maximum induction vacuum is limited by a BCD valve or the like, an embodiment anticipates the change in induction characteristics based on the engine speed.

Abstract: An engine control system introduces a technology of assuming actually required fuel amount to be delivered to each engine cylinder at opening timing of an intake valve of the engine cylinder. In order to derive the assumed fuel demand, a basic fuel supply amount is derived on the basis of a basic fuel supply control parameter including an engine speed data and an intake air amount representative data, an air induction path area variation ratio data and a lag time data from derivation of the air induction path area variation ratio data to opening of the intake valve. The assumed fuel demand data can be used not only for controlling fuel supply but also for spark ignition timing control, air/fuel ratio control and so forth so that the engine operation control may precisely follow the actual engine driving condition for optimizing the engine performance.

Abstract: An engine control method for a vehicle is disclosed in which operation of an engine is optimally controlled in an entire operating range thereof without causing any undesirable delay in control operation. To this end, operating conditions of the engine are sensed through the use of various sensors and control signals are calculated based on the sensed engine operating conditions in a plurality of steps through the use of a microcomputer so that the operation of the engine is optimized by the use of the control signals thus calculated. In one embodiment, a first step and a second step of the plurality of steps are alternately calculated and omitted every other time the control signals are calculated while an operating parameter of the engine operates in a specified operating range in which variations in the sensed operating conditions of the engine are limited.

Abstract: A fuel supply control system for an engine associated with a transmission for transmitting the engine output power to driving wheels of a vehicle increases the amount of fuel to be supplied to the engine when the engine is in a particular operating condition in which relatively large engine output power is required. The fuel supply control system receives a signal from a switch which is switched over according to whether the engine is associated with a manual transmission or an automatic transmission, and controls the amount by which the fuel to be supplied to the engine is increased when the engine is in the particular operating condition so that the amount is smaller when the engine is associated with an automatic transmission than when the engine is associated with a manual transmission.

Abstract: An air-fuel ratio control method for an internal combustion engine, wherein when the engine is in a feedback control region, a value of concentration of oxygen detected by the O.sub.2 sensor is compared with a predetermined reference value, and the air-fuel ratio of a mixture being supplied to the engine is controlled to a desired value in a feedback manner responsive to the comparison result. When the engine is in a predetermined high load operating region, the feedback control is interrrupted and an amount of fuel to be supplied to the engine is increased by a predetermined amount to thereby enrich the air-fuel ratio. The predetermined amount is increased when the engine is in the predetermined high load operating region and at the same time the detected oxygen concentration indicates that the air-fuel ratio is on a lean side with respect to the desired value.

Abstract: A method for feedback controlling air-fuel ratio of the mixture supplied to an internal combustion engine having a plurality of cylinders comprises the steps of, detecting respective air-fuel ratios of the exhaust gas from the respective cylinders with an air-fuel ratio sensor having a substantially linear output characteristic; calculating an average air-fuel ratio by using the latest detected air-fuel ratios of the respective cylinders; determining a fundamental feedback correction coefficient .beta..sub.0 for a cylinder of which air fuel ratio is feedback controlled next; retrieving a learning correction coefficient .beta..sub.1 for the cylinder of which air-fuel ratio is feedback controlled next from a learning map prepared by learning for the corresponding cylinder; and determining new learning correction coefficients .beta..sub.

Abstract: A fuel injection controller for an internal combustion engine includes a control pulse generator which generates a pulse with each rotation of the crankshaft. An operating condition discriminator determines the operating condition of the engine. An electronic control unit changes from sequential fuel injection to simultaneous fuel injection without degradation of engine performance. An ignition controller has first, and third pulse generators generating pulses with rotation of the crankshaft and camshaft, respectively, and a second pulse generator pulsing at a phase angle with respect to the crankshaft. An ignition timer controls ignition timing based on the pulses from the first and second pulse generators, and a fuel injection timer controls fuel injection based on the pulses from the first and third pulse generators.

Abstract: A known control system for adjusting the lambda value of an internal combustion engine includes a corrective value ROM for transient operation wherein corrective values are stored for correcting the injection times for transient operation. In contrast thereto, the system according to the invention includes a corrective base value ROM 30, an adaptation value RAM 35 and an adaptation unit 34. The values from the corrective base value ROM are not utilized directly for correcting injection times; instead, these values serve as corrective base values which only become adapted corrective values by means of multiplication with adaptation values. The adaptation unit adapts the adaptation values in the adaptation value RAM. For this purpose, the adaptation unit determines the lambda value control deviations during a transient operation.

Abstract: The quantity of air inducted in a cylinder of an engine is estimated by using equations based on various coefficients. The coefficients are stored in a memory and derived in accordance with engine operating conditions. A basic injection pulse width is calculated by the estimated inducted air quantity and speed of the engine. The basic injection pulse width is corrected by a feedback coefficient, thereby producing a fuel injection pulse width signal for operating a fuel injector of the engine.

Abstract: A fuel injection control apparatus comprises a load detecting means to detect a load to an engine to thereby generate a signal, a basic injection quantity operating means to operate the signal so as to obtain the pulse width of a basic fuel-injection time for a fuel injector in response to the condition of load, and a limiting means which conducts a dulling treatment to the basic fuel injection pulse width so that limitation of the fuel injection pulse width of the fuel injector in response to a value modified by the dulling treatment is determined on the basis of a limit value correction coefficient in accordance with the condition of load.

Abstract: A basic injection quantity is determined by engine speed and intake passage pressure. The pressure is estimated from engine speed and throttle position, and changing rate of the estimated pressure is calculated. A correcting quantity is obtained from the changing rate of the estimated pressure. The basic injection quantity is corrected with the correcting quantity.

Abstract: A fuel injection control device for controlling a synchronous injection time period and an asynchronous injection time period. When the synchronous injection time period calculated from the operating state of the engine exceeds one time period of the synchronous injection, the actual synchronous injection time period is restricted so that it does not exceed one time period of the synchronous injection. When the request for the asynchronous injection occurs during the time the synchronous injection is carried out, the actual synchronous injection time period is prolonged by the asynchronous injection time period.

Abstract: An air-fuel ratio feedback control method for an internal combustion engine, in which when the engine is operating in a feedback control region, the air-fuel ratio of an air-fuel mixture being supplied to the engine is controlled by the use of a correction coefficient varying in response to the output of an exhaust gas ingredient concentration sensor arranged in the exhaust system of the engine. When the engine has shifted to a predetermined high load region within the feedback control region, in which the rate of change in values of an engine operating parameter is larger than a predetermined value, the air-fuel ratio feedback control is effected by the use of a first average value of the correction coefficient, calculated when the engine is in the predetermined high load region.

Abstract: A fuel injection control system is directed a sequential injection type fuel injection internal combustion engine for injecting fuel to each engine cylinder at different timings. Acceleration enrichment asynchronous fuel injection is initiated in response to an acceleration demand. Acceleration enrichment is further performed for subsequent injection cycles to compensate for engine load indicative sensor signals which differ from actual engine load due to errors in an air flow meter.

Abstract: An apparatus for use with a multi-cylinder internal combustion engine including a plurality of fuel injectors, each being operable in its open position for injecting fuel into an intake port with which an intake valve is in cooperation for regulating the entry of combustion ingredients into the corresponding cylinder. The apparatus includes a control circuit for operating the fuel injectors in a predetermined sequence. The control circuit determines a length of time one fuel injector to be operated is in its open position in response to selected engine operating conditions. The control circuit opens the one fuel injector at a time to terminate the determined time length substantially at the same time when the corresponding intake valve opens. In addition, the control circuit prolongs the determined time length in response to a demand for engine acceleration produced when the one fuel injector is in its open position.

Abstract: The electronic controller for an internal combustion engine is adapted to reduce an output power of the internal combustion engine by controlling a fuel supply quantity or an ignition angle during a predetermined duration from a timing when a vehicle was brought into an accelerated condition, so that an output power of the engine is reduced for an predetermined duration before the first positive peak of a acceleration vibration of the vehicle is generated with an increase of the output power of the engine to suppress the acceleration vibration in longitudinal direction.

Abstract: An internal combustion engine control apparatus in which upon detection of transient state of the engine such as acceleration, deceleration or the like, the amount of fuel supply to the engine is corrected by using transient correcting coefficients which are determined previously and updated through learning procedure. The correcting coefficient is updated on the basis of the result of comparison of the air-fuel ratio detected upon occurrance of the transient state with a predetermined reference value.

Abstract: Disclosed herein is an air/fuel ratio controller for an engine, which is equipped with a function to make the air/fuel ratio leaner in a light-load operation zone or the like of a lean burn engine. The controller is intended to improve the starting performance and acceleration feeling of the engine significantly. Upon generation of an acceleration command by a driver during lean burn of the engine at a lean air/fuel ratio, an air/fuel ratio enriching device is operated to set the air/fuel ratio of an air-fuel mixture, which is to be fed to the engine, at a level richer than the lean air/fuel ratio while an actually accelerated state continues in the engine from the time point of generation of the acceleration command.

Abstract: An air/fuel ratio control system is designed for detecting small deceleration and subsequently detecting small magnitude acceleration. When small magnitude acceleration is detected, a LAMBDA control correction value which is utilized for deriving fuel injection amount, is fixed at a predetermined value for a predetermined period. The air/fuel ratio utilized during the aforementioned period is set at a value greater than the instantaneous value at a timing at which a demand for small magnitude acceleration is detected.

Abstract: An adaptive control system for categorized engine conditions is disclosed in which the engine conditions to be controlled are discriminated and classified in accordance with the driver's intent and the vehicle operating conditions. It is decided that a given engine control condition is continued or the transition is under way between different control conditions as a history judgement, and a vehicle operation parameter is determined in accordance with the determined history. At the same time, in accordance with the control condition decided and classified, an operating signal is applied to the engine with an operating parameter thus determined and the result of engine control response is observed to update the adaptive parameter.

Abstract: A system and method for controlling a fuel supplied to an internal combustion engine having a fuel supply cut-off function which operates when the engine falls in a predetermined engine deceleration condition. When a fuel supply recovery is restarted immediately after the fuel supply cut-off, a residual quantity of fuel which remains on a wall of an intake air passage is estimated on the basis of an engine load immediately before the fuel supply cut-off is carried out, a fuel recovery increment quantity for incrementing the fuel supply to the engine at a time immediately after the fuel supply recovery is carried out is set on the basis of the estimated residual quantity of fuel and an interval of time for which the fuel supply cut-off is carried out, a basic fuel quantity determined according to an engine operating condition is corrected according to the fuel recovery increment quantity, and the corrected fuel quantity is finally supplied to the engine during the fuel supply recovery.

Abstract: An asynchronous fuel injection control method for engines where the amount of increase of air sucked into the cylinder of the engine corresponding to the variation of the throttle angle is estimated on the basis of a physical model formula expressing the amount of the sucked air in the cylinder, and a pulse width according to which the fuel is injected by the asynchronous injection into the engine is determined on the basis of the estimated amount of increase of the sucked air.

Abstract: The invention relates to a process for fuel metering during acceleration operations at a plurality of cylinders of an internal-combustion engine, with sequential injection, in which the fuel quantity to be injected is determined corresponding to the operating state and the acceleration state is determined, additional fuel injections being performed after determination of the acceleration state. Such a process is to be further developed to the extent that a faster metering of the increased fuel quantity into the internal-combustion engine can be performed during the acceleration operation. To achieve this object, it is proposed that the determined fuel quantity is injected into at least one, preferably into all those cylinders whose injected fuel quantity has not yet been taken in and whose inlet valve has not yet been closed or whose intake stroke has not yet been concluded.

Abstract: To control the quantity of fuel supplied to an I.C. engine, a sensor generates an exhaust gas component concentration signal. If the present fuel supply quantity does not exceed a reference quantity, the fuel supply is set according to engine operation parameters. If the preset quantity is greater than the reference quantity for a predetermined reference time, the fuel supply is set without regard to the signal. The reference time is changed as a function of engine temperature.

Abstract: A fuel injection control system is directed for a sequential injection type fuel injection internal combustion engine for injecting fuel for each engine cylinder at different timing. Acceleration enrichment asynchroneous fuel injection is initiated in response to an acceleration demand. Acceleration enrichment is further performed for subsequent given injection cycles for compensation of smaller engine load indicative sensor signal than actual engine load due to error in an air flow meter.

Abstract: A system and method for determining and controlling the mixture ratio of an air-fuel mixture supplied to an internal combustion engine in which the air-fuel mixture ratio is estimated from a maximum internal pressure of an engine cylinder. The estimated air-fuel mixture ratio is then positively ascertained on the basis of a determination result derived by a weighting processing calculation of input signals indicating various engine and vehicle operating conditions affecting the change in the air-fuel mixture ratio using a weight vector with a reference signal. The air-fuel mixture is controlled on the basis of the ascertained air-fuel mixture ratio. Furthermore, each parameter of the weight vector is learned and corrected in a direction toward which a correct percentage of the determination of the rich-side or lean-side air-fuel mixture ratio by the weight calculation is increased.

Abstract: A method for controlling fuel injection rate in internal combustion engine in accordance with the intake pressure and the engine speed. The method has the steps of determining the intake pressure using, as a variable, the period of time after a change in the throttle opening, and computing a basic fuel injection period on the basis of the thus computed intake pressure and the engine speed. The fuel injection is conducted by a system in accordance with this method. The system determines the intake pressure in the steady state of engine operation in accordance with the throttle opening and the fuel injection rate, effects a correction on the thus determined intake pressure so as to take into account a delay in response of the intake pressure to the transient period, and determines the basic fuel injection period on the basis of the corrected intake pressure and the engine speed.

Abstract: A basic injection pulse width is derived from a table in accordance with speed of an engine and throttle position of a throttle valve of the engine. A time constant for providing a first order lag is calculated from variables dependent on the engine speed and the throttle position. The basic injection pulse width is corrected with the time constant, thereby producing a fuel injection pulse width signal for operating a fuel injector of the engine.

Abstract: An engine control method and device for a vehicle are disclosed in which jerk in the body of a vehicle developing upon acceleration or deceleration thereof can be always made substantially constant so as to improve riding comfort. Also, pitching or surging of the vehicle body during acceleration or deceleration thereof is substantially alleviated or suppressed even when the operator abruptly operates an accelerator pedal, thereby further improving riding comfort. To this end, a target degree of opening of a throttle valve is first set based on at least one of the sensed amount of accelerator pedal operation, the sensed engine load condition and the sensed number of revolutions per minute of the engine. The throttle valve operatively associated with the accelerator pedal is controlled in such a manner that, when the accelerator pedal is operated by the operator, the throttle valve is operated to move to the target degree of opening in synchronization with the intake stroke of the engine as sensed.

Abstract: A fuel supply control method for a multicylinder internal combustion engine equipped with a fuel supply control system including a main fuel injection valve disposed in the intake passage upstream of the throttle valve, and an auxiliary fuel injection valve disposed in the intake passage downstream of the throttle valve and upstream of the intake manifold, for controlling the fuel supply control system according to operating conditions of the engine.

Abstract: An air/fuel control system for a supercharged automotive engine includes a supercharger for supercharging air to be supplied to the engine, a detecting device for detecting a plurality of parameters representative of an engine operating condition, an air/fuel ratio regulating unit for adjusting the air/fuel mixing ratio to an arbitrarily chosen predetermined value, and a control unit for controlling the air/fuel ratio regulating unit. The control unit is designed to cause the air/fuel ratio regulating unit to adjust the air/fuel mixing ratio to a predetermined value higher than the stoichiometric value when the detecting device indicates that the engine is in a normal operating condition while the supercharger is operated, and also to adjust the air/fuel mixing ratio to a predetermined value lower than the stoichiometric value when the detecting device indicates that the engine is under an operating condition in which a relatively high engine power output is required.

Abstract: The throttle valve position of an engine is sensed and the effective cross sectional area of the induction passage is determined via table look-up. The table is recorded in terms of three parameters. The value thus derived is divided by the engine speed of alternatively a product of the engine speed and the engine displacement. A basic air induction quantity is then determined via table look-up and is subsequently modified using a correction coefficient to allow for the effect of engine speed on the same. The effect of injector position (viz., multi-point injection/single point injection) and/or the provision of a swirl control valve can be additionally taken into consideration via the use of suitable algorithms or additional two and three parameter system tables. If an idle control by-pass passage is provided, the effect of the opening degree is considered when determining the effective cross-section of the induction passage.

Abstract: In a fuel control apparatus by which a basic fuel quantity T.sub.p is first calculated on the basis of a detected intake air flow rate Q and a detected engine speed N as T.sub.p =KQ/N (K: constant) and the calculated basic fuel quantity T.sub.p is corrected on the basis of a correction coefficient COEF related to various engine operating conditions (e.g. coolant temperature), air/fuel ratio feedback correction coefficient .alpha., and a battery voltage correction coefficient T.sub.s as T.sub.i =T.sub.p .times.COEF.times..alpha.+T.sub.s, when an engine is accelerated, an initial fuel increment coefficient KAC.sub.0 is determined on the basis of throttle opening rate and engine speed, and added to the correction coefficient as COEF+KAC.sub.0, and thereafter the initial fuel increment coefficient KAC.sub.0 is reduced at a small coefficient decrement rate DKAC.sub.1 at lower engine speed to prevent hesitation, but at a large coefficient decrement rate DKAC.sub.

Abstract: An electronically-controlled fuel injection system having a synchronous counter which receives main injection time data corresponding to an amount of fuel to be injected synchronously to engine revolutions, and an asynchronous counter which receives increment injection time data corresponding to an amount of fuel to be injected at a selected time interval asynchronously to the engine revolutions, wherein the synchronous counter is operated for a period of time equal to the main injection time data upon receiving a synchronous signal which is generated synchronously to the engine revolutions, while the asynchronous counter is operated for a period of time equal to the increment injection time data upon receiving an asynchronous signal which is generated at the selected time interval, so as to open a fuel injection valve by pulses which are output from the respective counters during the operations thereof.