Abstract: A method of operating a drive circuit of a solenoid of an electromagnetic device including an armature, the drive circuit including switch means in series with the solenoid, comprising closing the switch means to achieve a high rate of current increase in the solenoid, opening the switch means when the current reaches a predetermined level and allowing the current to decay, the movement of the armature from a first to a second position being completed whilst the current is decaying and monitoring the decaying current using a sensing circuit which includes means responsive to a discontinuity in the decaying current flow when the armature reaches the second position.

Abstract: A method for triggering an electromagnetic consumer with low coil resistance (solenoid for a Diesel injection pump) having a free-running circuit that can be switched over, and an apparatus for performing the method, regulate a voltage at an end stage to a predetermined value. This is accomplished by controlling the control voltage of the end stage during a turn-on phase until a turn-on peak current is reached and then regulating the holding current by repeatedly lowering the current through the end stage and keeping it constant to a predetermined value during a predetermined time period and then raising it again to a maximum value of the holding current until the consumer is turned off.

Abstract: A fuel injector control circuit is disclosed. The circuits can be used with a plurality of different fuel injectors and can be programmed to produce a plurality of different injector current waveforms. The control preferably includes a microprocessor with memory connected to a multiplexer and an application specific integrated circuit. The control can also be used to increase the current rise time of a specific injector current waveform.

Abstract: An internal combustion engine assembly including a solenoid pump having an armature and a solenoid winding encircling the armature such that the armature moves in response to current flow, including unwanted current variations, through the solenoid winding and a control circuit connected to the solenoid winding for detecting unwanted variable current flow in the solenoid winding and for controlling actual current flow in the solenoid winding in response to the detected unwanted variable current flow to thereby precisely control movement of the armature.

Abstract: A fuel injection method for multicylinder internal combustion engines uses output signals of at least one camshaft sensor. A determination is made as a function of an engine or coolant temperature and an output signal of a camshaft sensor, in which cylinder of the internal combustion engine a fuel preinjection should take place prior to synchronization.

Abstract: Supply of fuel is stopped when fuel pressure sensed by a pressure sensor provided upstream of a regulator is at a predetermined value or less to avoid abnormal combustion caused by improper adjustment of air/fuel ratio. Even slight variation of the fuel pressure is sensed by monitoring the fuel pressure in an interval after closing a fuel shut-off valve once opened to re-opening of it. In addition, an abnormal state in the fuel system is detected by comparing an accumulated value of amount of injected fuel and an estimated value of fuel consumption in the tank. Furthermore, the peak current value of the fuel injection valve is controlled so that, when the engine at a low temperature is started, lift load of the injection valve is larger than sticking force of the injection valve, thereby preventing such situation where the injection valve is frozen so that it cannot supply fuel to the engine. In this case, the engine can be smoothly started by simultaneously controlling the valve open time.

Abstract: This invention relates to driving solenoid and motor loads while providing the means for fast turn on and fast turn off. Many applications including automotive fuel injector drivers, Anti-Skid Braking (ABS) solenoid and motor drivers, and other electro-mechanical motion control require the ability to quickly turn on or off a number of devices. The invention utilizes a bridge architecture to drive the loads and to turn on and off individual devices. The invention employs a diode and a switch for each device controlled plus a single master diode and a single master switch. The invention thereby reduces the number of components needed to control N devices to 2*N+2 from prior art half bridge circuit 4*N. Novel techniques and algorithms are used to multiplex the single master switch and control multiple inductive devices. The system provides redundant control and error checking means to preclude single point failure mechanisms.

Abstract: A method and a device for actuating an electromagnetic load, in particular a solenoid valve, for influencing the metering of fuel in a diesel internal combustion engine. The load is connected in series with a switching means which is supplied with an actuation signal. In order to identify a switching time of the electromagnetic load, a parameter which characterizes the actuation signal is evaluated.

Abstract: In a method and device for driving an electromagnetic load, especially a solenoid valve, which influences the fuel quantity to be injected into an internal combustion engine, the duration of the drive of the solenoid valve can be corrected by a delay time. The delay time can be predetermined as a function of the power supplied to the load.

Abstract: A method for driving an injector for feeding an internal combustion engine with fuel which is capable of improving starting characteristics of the engine. A power circuit is provided which functions to charge a power capacitor utilizing an output of a generating coil, so that feeding of an injection command signal permits a driving current to flow through a driving coil of an injector. A period of time required to permit charges in an amount necessary to drive the injector to be accumulated in the power capacitor is defined to be an injector drive prohibition period, during which generation of the injection command signal is prohibited, to thereby prohibit flowing of the driving current. The injector drive prohibition period is elapsed, so that a required amount of charges are accumulated in the power capacitor, followed by generation of the injection command signal, to thereby permit the driving current to flow the driving coil.

Abstract: A control circuit for supplying a load with current having a high-amplitude ortion with a rapid leading edge, and a lower-amplitude portion. The circuit is input-connected to a low-voltage supply source, and comprises a number of actuator circuits parallel-connected between the input terminals and each including a capacitor and a load. Each actuator circuit also comprises a first controlled switch between the respective load and a reference line, for enabling energy supply and storage by the respective load. A second controlled switch is provided between the capacitor line and the load line, for rapidly discharging the capacitors into the load selected by the first switch and recirculating the load current, or for charging the capacitors with the recirculated load current.

Abstract: After an injector current for opening a fuel injector is fed thereto, energization on the fuel injector is stopped to reduce the injector current towards a holding current level for keeping the fuel injector at an open state, a flywheel circuit being inoperative. Before a closed loop for controlling the injector current at the holding current level is formed, the flywheel circuit is made operative, whereby an influence of the operational delay of a circuit forming the closed loop can be reduced and further the injector current can be swiftly transferred to the holding current level before it falls largely.

Abstract: A fuel injection equipment for an internal combustion engine capable of reducing a variation in fuel injection time due to a variation in power supply voltage. An injector is incorporated which is constructed so as to exhibit characteristics which permit ineffective time consumed between start of flowing of an exciting current and actual opening of a valve to converge on a constant value while being gradually reduced with an increase in driving voltage. The driving voltage is set to be a value increased sufficient to permit a ratio of variation of the ineffective time to the driving voltage to be within a tolerance.

Abstract: An excess voltage applied to a piezoelectric element is detected and controlled to improve durability and reliability of the piezoelectric element. A fuel injection control device for an internal combustion engine in which a power source voltage is boosted by a dc-dc converter and the so-boosted output voltage is supplied via a first choke coil and a first thyristor to a piezoelectric element for charging the piezoelectric element, the electric charge of which is subsequently discharged via a second thyristor and a second choke coil. The fuel injection control device includes a positive voltage detection unit for detecting an excess voltage arranged between the first choke coil and the first thyristor and a positive voltage control unit controlled by an output signal of the positive voltage detection unit and adapted for shorting both ends of the first choke coil. The current through the first thyristor is cutoff to prevent the excess voltage from being applied to the piezoelectric element.

Abstract: In a engine and associated fuel injector failure detection circuit, the engine having at least one combustion chamber, a battery, and at least one fuel injector having a high side and a low side terminal for introducing a fuel in the at least one combustion chamber, the fuel injector failure detection circuit comprising a one shot timer for transmitting a constant voltage state signal output when the fuel injector reaches a set current threshold at a start of an injector current peak time duration. A voltage sense comparator is provided for transmitting a low voltage state signal output when the low side terminal of the fuel injector produces a fly-back voltage pulse. A mechanism for monitoring current of the fuel injector during a rise time duration and the peak time duration ia also included.

Abstract: In a non-stage transmission control system, the output current instruction signal of a microcomputer is provided as a pulse-width-modulated signal, with a result that the number of signal lines from the microcomputer is reduced. Furthermore, the current feedback signal of a solenoid is applied to the microcomputer, for detection of abnormal conditions, and a quick break resistor is connected in series to a feedback diode to increase the current reduction rate of the solenoid.

Abstract: A current flowing to a fuel injector is completely cut off when an injection pulse signal is OFF at a timing to stop conduction of the fuel injector to reliability close the fuel injector, and when an injection pulse signal is OFF at a timing to stop conduction of an injector, an output transistor of a comparator is on to forcibly set a base potential of a switching transistor to a low level so as to completely cut off the switching transistor. At this time, a control signal output of an AND gate becomes a logic "0", but an actual signal voltage does not become completely "0", but even when a comparator is erroneously operated, the switching transistor is completely cut off by the comparator, and hence no current flows to the injector, and a small current continuously does not flow to the injector to prevent a valve closing force from being weakened.

Abstract: Apparatus and method for controlling current flow through a magnetic coil actuator of a solenoid valve. The current through the magnetic coil is measured by sensing the voltage drop across a precision resistor in series with the coil. The apparatus includes a power switch for alternately switching the coil on and off. A flyback diode is coupled in parallel with the coil for operation during coil shut-off. A first voltage sensor continuously measures the combined voltage drop across the coil and the power switch. A second sensor, coupled across the precision resistor, samples the current flowing through the coil. The samplings occur synchronously with coil turn-on, and are delayed by a predetermined time delay which is long enough to allow the current flowing through the coil to reach steady state before the current is sampled. Circuitry is provided for employing the sensed voltage signal and current samplings to produce a signal whose value is a function of the resistive component of coil impedance.

Abstract: An electronic fuel injector driver circuit is a high speed operator of electromagnetic fuel injector valves for internal combustion engine. The drive circuit includes a solenoid coil for each electromagnetic fuel injector. A one shot timer circuit sends a predetermined timing signal to a first controller circuit interconnecting the one shot timer circuit and the solenoid coil wherein the predetermined timing signal is used to control the high side of the solenoid coil. A second controller circuit is connected to the solenoid coil and controls the low side of the solenoid coil in response to the predetermined timing signal. A switchable voltage reference circuit is connected to the second controller circuit and controls current through the solenoid coil.

Abstract: Piezoelectric element used in a fuel injection value is to be improved in its response to expansion and contraction, while the supply of an excess energy to the piezoelectric element is to be controlled. In a fuel injection control device in which an output voltage of the dc-dc converter is applied to a piezoelectric element via a choke coil and a thyristor, a current detection unit is provided between the dc-dc converter and the thyristor. A measured value of the electric charge, as found by integrating a charging current flowing through the current detection unit is compared by a comparator to a command value of electrical charges as found by processing the dc-dc converter output voltage. The results of comparison are supplied to a latch unit so as to be latched at the timing of a peak value of the charging current.

Abstract: A pilot injection amount QP, a main injection amount QM, and a lag TDF between the main and pilot injections are obtained (S130). The pilot injection initiating timing TTP, the pilot injection period TP, the main injection initiating timing TTM, and the main injection period TM are obtained on the basis of the pilot injection amount QP, the main injection amount QM, the fundamental injection initiating timing KT and the common rail pressure Pc (S150). The main injection period correction amount .DELTA.TQM and the injection initiating timing correction shift amount .DELTA.T are then obtained on the basis of the pilot injection period TP and the time lag TDF (S160). Finally, modified by these correction amount .DELTA.TQM and the shift amount .DELTA.T, the pilot injection initiating timing TTP', the main injection initiating timing TTM' and the main injection period TM' are obtained as final values (S170).

Abstract: An electrical supply and switching circuit for the electrical fuel injectors of a fuel injection engine wherein a separate voltage supply circuit is provided for both the control circuit and driver circuit to minimize the effects of noise.

Abstract: An electronic fuel admission system for use in an industrial engine or the like, having high speed electrically operated flow control valve assemblies for controlling fuel flow to the engine's cylinders via an air intake system is disclosed. The valve assembly comprises two opposed face-to-face disks; one disk being fixed, the other being translatable with respect to the fixed disk. Both disks include ports distributed around their surfaces such that flow is prevented when the disks abut yet a slight separation results in a relatively high flow rate. The translatable disk is connected to an armature which is associated with a high permeability magnetic core having a coil for generating magnetic flux within the core. The system includes a two phase driver for energizing the coil which first provides a high current of short duration to rapidly generate flux in the core and rapidly attract the armature thereby separating the translatable disk from the fixed disk and opening the valve.

Abstract: A fuel injection control system for an internal combustion engine which can eliminate lean misfiring and rich misfiring at asynchronous injection and exhausting of non-combustioned HC. When the asynchronous injection is performed at engine cranking or at acceleration, a judgement is made as to whether the injected fuel will be divided by closure of an intake valve. When division is not detected, fuel injection is performed in normal manner. When division is detected, rate of the fuel division is computed. As a result of computation, fuel injection is performed when judgement is made that a predetermined amount of the injected fuel will be introduced into the cylinder. Furthermore, the amount of fuel not introduced into the cylinder is computed to reduce a corresponding amount from a fuel injection amount for the next cycle. On the other hand, when judgement is made that the predetermined amount of fuel will not be introduced into the cylinder, fuel injection does not take place.

Abstract: In the case of a method and a device for triggering an electromagnetic consumer (1), which is connected in series to a switching means (2), the voltage applied to the switching means (2) is fed to a voltage comparison means (12) and compared there to the voltage of a reference voltage source (13). Dependent upon this voltage comparison, an output signal is produced at the output terminal of the voltage comparison means (12), which serves to switch over a suppressor device (4).

Abstract: A non-return fuel distribution system or deadheaded fuel distribution system for an internal combustion engine having one or more fuel injectors mounted on a fuel rail on the engine, has a fuel pressure transducer mounted on the fuel rail to sense the fuel pressure in the rail and generate an electrical signal representing such pressure. The electrical signal is combined in a controller to operate an electrically operated variable pressure fuel pump to generate and maintain the fuel pressure necessary to operate the electrically operated fuel injectors in their linear operating pulse range.

Abstract: A circuit comprising a switch series connected to a load; a first and second current recirculating branch alternately connectable parallel to the load, for reducing the current in the same; and a logic control unit for opening and closing the switch and recirculating branches, so that the load is supplied with a current rising to a peak value and then falling rapidly to and oscillating about a lower hold value; a transistor being provided for reducing the voltage supplied to the load by the first recirculating branch at the end of the fast fall phase, so as to eliminate uncontrollable operating zones and prevent the load current from falling below the hold value.

Abstract: The invention relates to an electronic circuit arrangement for triggering excitation windings of electromagnetic components, provided with supplementary circuit elements, in particular free-running circuit elements, preferably solenoid valves (MV.sub.1 to MV.sub.n), whereby in order to provide a flexible open-loop control, the components are each connected in series to a controllable contact element (3). To reduce the degree of complexity of the circuit, the manufacturing price and the space requirement, it is proposed that the connecting terminals (1, 4) of this series connection lead directly, and the connections (2) between the components (MV.sub.1 to MV.sub.n) and the contact elements (3) lead via diodes (D.sub.1 to D.sub.n), respectively, to a collecting point (A, B, C), to which collecting points (A, B, C) is linked one and the same supplementary circuit-element configuration (T.sub.F,C.sub.L,10,11) shared by all components.

Abstract: A fuel injection equipment including a fuel injector for injecting fuel into a fuel injected space of an internal combustion engine and a fuel pump is disclosed. A generator which is driven by the internal combustion engine and has characteristics of being increased in output voltage or output current with an increase in engine rotation speed is used as any one of an injector driving power supply for feeding the fuel injector with an exciting current through an injector trigger circuit and a fuel pump driving power supply. Use of the generator as the power supply permits the fuel injection equipment to be controlled without requiring a complicated control circuit.

Abstract: A modular switching system includes a transistor operative in a switching mode for applying current to a load. Adaptation of the system to accommodate different values of load is attained by coupling an input drive ,signal to a base terminal of the transistor via a variable gain amplifier wherein the gain is established by a load-adaption signal to meet the requisite base current drive signal for the load. Plural emitter terminals of the transistor connected to separate branches of a monitoring circuit, each branch having its own threshold detector, for monitoring of minimum and maximum values of load current.

Abstract: A fuel-injection device adjusts a fuel-injection level with a solenoid valve disposed in a fuel-supply passage which supplies the fuel to a compressor. A pulse width of a drive pulse to actuate the solenoid valve, which is determined by the sum of a time lag in the valve's closing caused by the motion of the valve member of the solenoid valve and of the time length at which the valve is to remain closed, is made shorter than the time lag in the valve's closing when the engine load is low. Current supplied to the solenoid is thus cut off immediately before the solenoid valve is completely closed, and a preflow caused by a rise in injection-pressure is reduced.

Abstract: A method of controlling the operation of a solenoid comprising supplying current to the solenoid winding from an electrical source and controlling the rate of rise of the current at a predetermined rate during at least the period between initiation of the current supply and the commencement of movement of the solenoid armature, said predetermined rate of rise of the current being independent of the maximum rate of rise of the current, attainable at the nominal voltage of the electrical source.

Abstract: A solenoid driving circuit for an automatic transmission in which a potential difference compensating device, such as a Darlington-connected transistor circuit, switching transistor, and/or diode, is connected between a resistance element and a power ground, and a controlling device monitors voltage values at opposite sides of the resistor element so as to detect a current value flowing across a solenoid. The controlling device determines whether the detected value of the current flowing across the solenoid is abnormal, and the controlling device shuts off the current of a solenoid driving device when it is abnormal. The potential difference compensating device is provided with a switching device, and the controlling device turns off the switching device when the monitoring current value is abnormal.

Abstract: A trigger circuit for an electromagnetic device, in particular a solenoid valve of an injection system for an internal-combustion engine, has a control element for causing excitation of the electromagnetic device to be lowered at least once and then raised after the electromagnetic device is activated. The control element has a delay circuit which slows down the rate at which excitation of the electromagnetic device changes during the lowering and/or raising action.

Abstract: A fuel injection system for an internal combustion engine capable of being normally operated while using an output of a generator driven by the internal combustion engine as a power supply therefor. The system includes a switching circuit for switching a driving current fed to an injector from a main power circuit which uses the output of the generator as a power supply therefor. The switching circuit is controlled by a switch control circuit for which a power supply comprises a control power circuit. The control power circuit includes a storage unit for storing electric power therein, so that the storage unit may be act as a power supply when the output of the main power circuit is reduced, to thereby feed the switch control circuit with a power supply voltage of a level equal to or above an operable level.

Abstract: A supply circuit is provided for operation of an electromagnetic load of a vehicle provided with generator (dynamo) and battery, and more particularly for operation of at least one solenoid valve of a fuel-injection system of an internal-combustion engine of the vehicle. A circuit arrangement is proposed which connects the load (6) for a buildup of its excitation to the generator (3) and then establishes a connection to the battery (13) for the maintenance of sufficient excitation and interrupts the connection to the generator (3).

Abstract: A fuel injection valve for internal combustion engines is disclosed, in which a transducer is vibrated by an electrostrictive device, and the fuel is atomized by a vibration surface at the part of the transducer where the amplitude thereof is maximum. The transducer has a path for transporting the fuel to the vibration surface. The fuel transport path may have midway thereof a valve member with a valve seat adapted to rise for opening the transport path when a predetermined vibration is exerted on the transducer.

Abstract: A method and apparatus for electronically detecting when a solenoid has closed, or nearly closed, indirectly senses changes in the inductance of the solenoid's coil as the solenoid closes. When the inductance has changed by a selected amount, the solenoid is assumed to have closed, or nearly closed, and current through the coil is promptly reduced. Preferably, changes in the inductance of the coil are sensed by establishing a plurality of current peaks in the coil, and sensing the current's decay time between peaks. When the decay time of a measured current peak exceeds the decay time of a previously measured current peak by a selected amount, it is assumed that the solenoid has closed, or nearly closed.

Abstract: An arrangement for injecting fuel for an internal combustion engine has at least one inductive injection valve which is switch controlled via a controllable semiconductor switch. This injection valve is provided with an inductive or capacitive oscillator component for atomizing fuel. During the switching control operation, electrical energy from the inductive injection valve is fed into the oscillator component for exciting its oscillating movement each time the semiconductor switch is opened. On the one hand, with this arrangement no separate high frequency generator is required for the oscillator component while, on the other hand, a second transistor is not required for the switch-controlled output stage with a rapid discharge without loss being possible at least in principle.

Abstract: A fuel injection valve for internal combustion engines is disclosed, in which transducer is vibrated by an electrostrictive device, and the fuel is atomized by a vibration surface at the part of the transducer where the amplitude thereof is maximum. The transducer has a path or transporting the fuel to the vibration surface. The fuel transport path may have midway thereof a valve member with a valve seat adapted to rise for opening the transport path when a predetermined vibration is exerted on the transducer.

Abstract: The invention is directed to a sequential fuel injection method wherein the first injection end time point is determined at which the preinjections end. In addition, the first intake end time point is determined at which a signal occurs for the first time after the start of the method which is evaluated as a signal that indicates the end of an induction operation. Furthermore, a determination is made for which cylinder the above-mentioned time point applies. If the first-mentioned time point lies ahead of the second-mentioned time point, the sequential fuel injection is started for the determined cylinder. For the opposite position of the mentioned time points, the injection valve for that particular cylinder is driven whose induction cycle follows the determined cylinder with the injection valve being so driven that the entire fuel quantity is injected which was computed for the sequential injection.

Abstract: An electronic driver circuit for the open loop control of the energization of a solenoid coil, forming part of an electromagnetic solenoid actuator valve, in response to a control pulse produced by a control circuit and where the predetermined schedules are a function of the inductance and resistance of the coil, the desired peak output voltage from the coil and the desired average holding current through the coil.

Abstract: In a circuit for controlling a pulsating current through an inductor, particularly the coil of an electromagnetic valve, the inductor is connected in series with a semiconductor switch and in parallel with a free-running diode. Furthermore a desired-value voltage is fed to a controller the output of which is connected via a pulse-width modulator to a control input of the semiconductor switch. A current flows through the inductor and the semiconductor switch, during a state of conduction of the semiconductor switch, to be measured. The current measurement is gated, in response to pulse-width modulation at the controller, and is then integrated for improved measurement of the current.

Abstract: A method and apparatus for controlling the operation of an electromagnet by comparing the frequency of its holding current pulses against a reference frequency and by initiating another energization cycle if a difference exceeding a predetermined value is detected.

Abstract: In a current detector for use with a pulse-driven electromagnetic actuator drive circuit, a solenoid current detector is disclosed which operates by use of a solenoid current detection resistor to sample an instantaneous solenoid current value at intervals of a predetermined pulse voltage period, and calculates the average current value for the solenoid by calculation based on the sampled value.

Abstract: A circuit for piloting an inductive load comprises a low-voltage supply, a storage inductor interposed between one pole of the supply and the load, a first electronic switch in parallel with the load, a second electronic switch in series with the load, between the load and the other pole of the supply, a third electronic switch interposed between the first pole of the supply and the junction between the load and the second switch, and an electronic control unit arranged to pilot the switches in a predetermined manner.The storage inductor is permanently connected to the first pole of the voltage supply and a conductive bypass path is provided between the first pole of the supply and the load. The control unit is arranged to cause the second and third electronic switches to open and close successively in counterphase, in order to maintain the current in the load at a predetermined average level.

Abstract: The circuit according to the invention comprises a hysteresis comparator 9 connected to a transistor 2 controlling the current flowing in an inductive load 1. The voltage taken across the terminals of a measurement resistor 3 is compared with a reference voltage established by a source 6. According to the invention, a feedback loop 10 establishes a proportional action of the transistor 2 on the current in the load 1 when the voltage at S exceeds a predetermined threshold. In this way an oscillation is obtained between two values on either side of a nominal value, these two values being associated with the thresholds of the hysteresis comparator. Application to the production of an integrated circuit for the control of the ignition coil of an internal combustion engine.

Abstract: In a process for fuel injection in a multiple-cylinder internal combustion engine, opening signals for the respective injection valves of the individual cylinders are produced as a function of reference signals which are synchronous with the crankshaft. All injection valves are first controlled jointly after the ignition switch is switched on and the sequential opening signals for the sequential fuel injection are produced after the synchronization has been recognized. In order that the sequential fuel injection be switched on rapidly after the start of the internal combustion engine or after a disruption of the synchronization, wherein the fuel quantity injected into opened inlet valves is to be minimized, the opening signals are fed to the injection valves in a simultaneous manner, at least in a phase (a) until the synchronization has been recognized.

Abstract: A circuit for controlling an inductive load for an electro-injector of a diesel-cycle internal combustion engine is operated from the vehicle battery and includes a reactive circuit having an energy-storage inductor. A first switch controls the supply of current to the energy-storage inductor and a second switch is provided for connecting the reactive circuit to the inductive load for rapid discharge of the energy stored in the energy-storage inductor load into the inductive so as to inject a current pulse into the load. A by-pass branch circuit is connected between the first switch and the load and includes additional switch for enabling the passage of current from the battery to the load when the first and second switches are simultaneously closed.

Abstract: A method of controlling fuel injection to an internal combustion engine by electronic circuits. A plurality of cylinders installed in the internal combustion engine are divided into two groups and two electronic circuits for controlling the respective two cylinder groups are provided. By comparing between the outputs of the two electronic circuits, whether the operations of the respective electronic circuits are normal or not is judged. The fuel injection controlled by the electronic circuit which has been judged to be abnormal is stopped, while the fuel injection controlled by the electronic circuit which has been judged to be normal is continued. Thus, the internal combustion engine is driven solely by one group of cylinders.