Abstract: A method for controlling an injection valve of an internal combustion engine, in particular a piezo-injector during the start-up phase of the internal combustion engine, in particular a common-rail direct-injection engine. The crankshaft of the internal combustion engine is rotated by the starting motor, in particular an electric starting motor. Next, the actuator of the injection valve has an activation signal applied to it such that when maximum needle lift of the actuator is reached, the activation signal is changed. This change of the activation signal is then evaluated.

Abstract: A device for driving a solenoid including a power supply, a switching element connected between the power supply and the solenoid in series therewith, a current circulating diode connected in parallel to the solenoid, a current detecting circuit for detecting an actual current flowing through the solenoid, and a PID computing unit for computing an on-duty value and an off-duty value according to a difference between a target current and the actual current detected and for outputting the on-duty value and the off-duty value. The device further includes a PWM duty driving unit for generating a PWM duty signal according to inputting of the on-duty value and supplying the PWM duty signal to the switching element to on/off control the switching element, and a reverse voltage applying circuit capable of applying a voltage of the power supply as a reverse voltage to the solenoid according to inputting of the off-duty value when the switching element is off.

Abstract: For controlling a magnetic flux of an electromagnet with a relay pulling characteristic and at least two stabile levels of values of a magnetic flux in a magnetic guide, controlling pulses of electric current are supplied into a winding of a magnetizing coil with obtaining a pulling force of a moving part of a magnetic guide of the electromagnet at least with one air gap, wherein the magnetic guide is formed at least partially of a magnetically hard material, two short-term pulses having an opposite polarity are supplied into the magnetizing coil on the magnetic guides of the electromagnet, for closing a magnetic circuit and minimization of magnetic resistance of the magnetic guide due, and holding or attracting force is provided until a supply of a second controlling pulse of electric current of the opposite polarity transferring the magnetic guide into a second stabile condition. Also, an electromagnet is proposed for an electromagnetic drive of an executing device.

Abstract: An arrangement comprising a magnetic body (12) having a hole portion (11) for passage of a primary-side first induction line (2), a primary-side second induction line (5) for electrically feeding a load in a contact less manner, an added line (17) passing through the hole portion (11) of the magnetic body, and 1th contact (19) for short-circuiting the added line 17. According to this arrangement, short-circuiting provided by the 1th contact (19) can cut off electric feeding to the primary-side second induction line (5), thereby isolating the load (second-side power receiving circuit) without mechanically switching the power supply line.

Abstract: The present invention achieves an increase in the amount of vapor that is expelled, stabilized fuel injection and improved starting characteristics in a fuel injection pump. In an electromagnetically driven fuel injection pump 20 which allows fuel to escape into the return passage 5 in the initial region of the pressure-feeding stroke of the plunger 21, and which pressure-feeds fuel into the injection port 33 in the later region of the pressure-feeding stroke, pulse powering of the coil 23 that does not lead to the injection of fuel, i.e., pulse powering which is such that the plunger 21 performs a reciprocating motion through the initial region, is performed when the engine 2 is in an idle operating state, or in a state in which the engine 2 is re-started after being stopped immediately following high-load operation.

Abstract: A control system for a fuel injector is disclosed. The control system has a valve element movable between a first position and a second position, an armature connected to the valve element, a solenoid configured to move the armature and connected valve element, and a controller in communication the solenoid. The controller is configured to energize the solenoid at a first current level to initiate movement of the valve element from the first position toward the second position, at a second current level less than the first current level during movement of the valve element from the first position toward the second position, at a third current level less than the second current level after the valve element has reached the second position, and at a fourth current level less than the third current level after the valve element has been in the second position for a predetermined period of time.

Abstract: The present invention relates to a method for operation of an electro-magnet (2, 3) connected to an intrinsically safe direct current circuit which can be switched under control between two positions for the operation of the closing body of a hydraulic valve (5, 6), whereby using of an electronic control unit, the coil windings of the electro-magnet (2, 3) are taken in the pull-in phase of the armature of the electro-magnet to an exciting current and in the retaining phase of the armature to a lower retaining current as opposed to the excitating current, and a device with which the retaining current reduction is realized.

Abstract: A method for controlling a fuel injector provided with an electrically operated electomagnetic actuator in such a manner as to open the injector for a determined injection time; the method providing that the injector be operated with a first current waveform if the injection time is greater than a predetermined threshold value, and that the injector be operated with a second current waveform if the injection time is less than the predetermined threshold value; both the current waveforms have an identical initial portion, during which the current passing through the injector is caused to rise until it reaches a peak value, which is maintained by cyclic switching of the voltage applied to the injector between two different values.

Abstract: An electric fluid dispenser for dispensing a fluid onto a substrate. A power switching circuit is connected to an unregulated power supply providing a varying voltage. A solenoid connected to the power switching circuit operates a dispensing valve to move between open and closed positions. A control circuit is responsive to the varying voltage from the power supply and provides a drive signal to the power switching circuit having a time variable component determined by the varying voltage. The power switching circuit, in response to the drive signal, provides an output signal to the solenoid that causes the dispensing valve to move between the open and closed positions substantially independent of the varying voltage from the unregulated power supply.

Abstract: A frequency-controlled load driver circuit includes a steady-state and a transient operational mode. A switching driver switches a load current to a solenoid at a set switching frequency during a steady-state operational mode. An analog-to-digital converter (ADC) oversamples a sense resistor voltage an integer number of times within each period of the switching frequency. A control circuit sets the switching frequency of the driver during the steady-state operational mode by providing predetermined switching times. The control circuit disables switching during the transient mode. Dither can be applied during the steady-state mode.

Abstract: Characteristics of micro electromechanical switches can be changed by applying a control signal which either changes one or more parameters of the micro electromechanical switches or which controls beam movement by feedback signals. It is thereby possible to change switching transient time, maximum switching frequency, power tolerance, and/or sensitivity (actuation voltage) of a micro electromechanical switch.

Abstract: Method for control of a proportional magnet comprising a magnet core, a magnet armature, a magnet coil for operating a control element in a shift valve or a proportional pressure-control valve, particularly a pressure-control valve for clutch operation in an automatic motor vehicle transmission, and comprising an electronic control device, whereby the magnet core may be moved back and forth between a control region and a hold region with a magnetic hold position of the magnet armature and a defined transition from the control region to the hold position may be executed and whereby mechanisms are provided for recognition of the movements of the magnet armature.

Abstract: A Brake Transmission Shift Interlock and Park Lock System having a shift lever, electromagnetic device, and blocking member operating with reverse logic. The system includes disabling means for disabling operation of the electromagnetic device when the shift lever is moved out of the PARK position and overriding means for manually withdrawing the blocking member from a position blocking the movement of the shift lever out of the PARK position. A time delay circuit decreases the speed of blocking member movement from the blocking position to the withdrawn position. A wire harness, including a park detection switch, electrically connects the BTSI to an automotive electrical system.

Abstract: A solenoid control circuit that includes two switching networks that are selectively opened and closed in a current limit cycle to control the magnitude of the current flowing through the solenoid. The configuration of the switching networks is such that current flows through an energy dissipating resistor only when the solenoid is commanded off by the solenoid control circuit, and not during the current limit cycle. Thus, the energy dissipated by this resistor is reduced relative to other solenoid control circuits, making it more efficient, and reducing EMI emissions from the circuit while providing for a fast solenoid response.

Abstract: In an electromagnetic contactor 100 for passing a current through an electromagnet 301 from a power source 402 and moving a movable core 1 from a first position in which a gap to a fixed core 20 is wide to a second position in which the gap is narrow by electromagnetic force and opening or closing a contact, there is provided an attraction force control part 303 for passing a strong acceleration current E1 through the electromagnet 301 for a predetermined time so that acceleration in the second position of the movable core 1 becomes a predetermined value and passing a suction current E6 through the electromagnet 301 in substantially the second position.

Abstract: An electromagnetically operated valve assembly (28) has a first solenoid (58) and a second solenoid (60). An armature (56) having a valve stem (54) coupled thereto is positioned between the first solenoid (58) and second solenoid (60). A controller (12) is coupled to the first solenoid (58), the second solenoid (60). A current sensor (49) is coupled to the first solenoid and generated a signal corresponding to the induced current in the first solenoid. The controller (12) changes a voltage applied to the first solenoid from a first polarity to a second polarity. The controller (12) is further configured to hold the voltage at the second polarity for a predetermined time period and a predetermined amplitude to decrease the induced current. The predetermined time period or the predetermined amplitude is determined based on the first signal.

Abstract: A device with a safety circuit with an armature activated by a solenoid activates an electromagnet. The device has a switch connected in series to the solenoid, a device temporarily interrupting application of the voltage, first and second clock generators, first and second resistors, and a current detection switch. DC voltage is applied to the solenoid when the switch is closed. The voltage is interrupted when a predetermined current flowing through the solenoid is detected. The first clock generator actuates the switch during a predetermined first clock cycle. The detection switch detects current flowing through the solenoid. The first resistor, in conjunction with the response threshold of the current detection switch, determines the holding current for the armature. The second resistor generates an attraction current for the armature when activated by the second clock generator in a predetermined second clock cycle partially overlapping the first clock cycle.

Abstract: An electromechanical valve assembly (46) for an internal combustion engine (36) is provided. The valve assembly (46) includes a rotor (68) centered about a first axis (122) having a bore (114) extending generally axially therethrough. The valve assembly (46) further includes a stator (66) operatively disposed about the rotor (68) for producing a torque to cause rotation of the rotor (68) about the axis (122). Finally, the valve assembly (46) includes a valve (70) having a valve stem (126) and a valve head (84). The valve stem (126) extends generally axially through the bore (114) of the rotor (68). The valve stem (126) is also configured to move generally axially responsive to the rotation of the rotor (68) to selectively engage and disengage the valve head (84) with a valve seat (124) of the engine (36).

Abstract: A method and device for triggering a solenoid valve for injecting fuel into an internal combustion engine is described. The triggering phase of the solenoid valve is subdivided into a pull-up phase and a holding phase. During the pull-up phase, a valve needle of the solenoid valve is caused to open by a first current intensity flowing through a magnetic coil of the solenoid valve. During the holding phase, the valve needle is held in the open state by a second, lower current intensity flowing through the magnetic coil. At least once at the beginning of the pull-up phase, a booster phase is activated during which a pulse-shaped booster current from a booster capacitor charged to a high voltage flows through the magnetic coil. During the triggering phase of the solenoid valve, a plurality of booster pulses are activated in succession, whose time position within the triggering phase is freely selectable.

Abstract: Device for energizing a number of coils of a hook selection device for a weaving machine includes an electrical power supply source connected to the coils and a regulating device for regulating the current intensity in the coils. Each coil includes: a comparator for comparing the current intensity in the coil to a reference current intensity and a controllable current regulator (e.g. a chopper transistor) for regulating the current intensity in the coil in order to reach or approach the reference current intensity. The regulating device includes an electronic control circuit that is provided to control the current regulator of each coil of a number of coils, in order to reduce a variance between the actual current intensity in that coil and the reference current intensity measured by the comparator of that coil.

Abstract: A method of controlling a fuel injector valve solenoid includes generating a set-point signal which models a desired current profile flowing through the valve solenoid, providing a current controller which is adapted to regulate the current flowing through the valve solenoid, and regulating the current flowing through the valve solenoid such that the current flowing through the valve solenoid closely matches the set point signal. Regulating the current includes measuring the current flowing through the valve solenoid, comparing the current flowing through the valve solenoid to the current profile of the set-point signal, and adjusting the current flowing through the valve solenoid to more closely match the current profile of the set-point signal.

Abstract: A device for controlling an electromechanical regulator, including a controller (3a) that controls the current through a coil (113) and which, for that purpose, generates control signals for a power regulator (5a). The control signals are determined with the coil (113) operating in the free-running operating state. The control signals depend, during the movement of the armature, on the current and the time differential of the current through the coil (113).

Abstract: An apparatus and a method for electromagnetically actuating engine valves to obtain soft seating. The magnitude and duration of current pulses applied to the armature attracting coils are determined based upon a total mechanical energy and a total energy loss of the armature obtained from the armature position.

Abstract: Driving circuitry for an electromagnetic fuel injection valve in which the holding current value is made variable to obtain a minimum necessary holding force from the holding current according to the fuel pressure includes a solenoid for driving the fuel injection valve, a capacitor charged by a high-voltage charge control part, a switch circuit for on-off controlling a high-voltage current supplied from the capacitor to the solenoid in response to an injection command signal, and a holding current supply circuit for supplying a holding current from the power supply to the solenoid. When the holding current is supplied, a comparator circuit compares a voltage obtained by converting the value of electric current flowing through the solenoid by a resistor for detection and a voltage corresponding to a fuel pressure sensor signal, and the value of the holding current is varied according to an output signal from the comparator circuit.

Abstract: A system (12) and method for controlling an armature (20) of an electromagnetic actuator (10) are provided. The system (12) includes a circuit (46) for providing current to the coils (32, 34) of electromagnets (16, 18) disposed on either side of the armature (20). The system (12) also includes an electronic control unit (ECU) (50). The ECU (50) is configured to determine the neutral position of a virtual spring corresponding to the combination of forces acting on the armature 20 including the magnetic force of the attracting electromagnet (16 or 18) and the force of a restoring spring (22 or 24) opposing movement of the armature (20) towards the attracting electromagnet (16 or 18). The ECU (50) is further configured to control the current in the coil (32 or 34) of the attracting electromagnet (16 or 18) responsive to the determined neutral position so as to minimize the velocity of the armature as it reaches the pole face (36 or 38) of the attracting electromagnet (16 or 18).

Abstract: An apparatus for detecting a low impedance load on an output of a driver circuit electrically connected to a coil of a fluid dispensing gun. The driver circuit provides a plurality of output signals to the coil in response to respective drive signals. Each drive signal has a waveform commanding the dispensing gun to open, and the waveform has a higher magnitude initial peak period followed by a lower magnitude hold period. A feedback circuit provides a difference signal as a function of a difference between each drive signal and a feedback of a corresponding output signal. A diagnostic circuit is connected to the driver circuit and provides an error signal representing a low impedance error as a function of the difference signal crossing a threshold signal magnitude during an occurrence of the peak period of the drive signal.

Abstract: A controller for an electromagnetic actuator comprises a pair of spring acting in opposite directions, and an armature coupled to a mechanical element. The armature is connected to the springs and held in a neutral position given by the springs when the actuator is not activated. The actuator includes a pair of electromagnets for driving the armature between two end positions. The controller includes voltage application means for applying voltage to an electromagnet providing one end position for a first predetermined period so as to attract the armature to the end position. The controller also includes a peak current detector for detecting the peak of current flowing through the electromagnet in the first predetermined period. In accordance with the peak value, a decision means decides the application period of voltage that is to be applied to the electromagnet after the first application period has elapsed.

Abstract: It is an object of the present invention to provide a controller for an internal combustion engine having a fuel injection system, which can realize an optimum injection even with a smaller inductance of a solenoid due to a smaller fuel injection valve (injector) and has a good property of minimum amount of fuel injection.

Abstract: In a transmission power control circuit according to the present invention, a variable gain amplifier (1) amplifies a transmitting wave with a gain corresponding to a control voltage VC from a power control section (110). When a transmission power (POUT) of the transmitting wave is within a measurable range of a detecting circuit (3), the power control section (110) sets a control voltage feedback ratio (K′) to 0 and applies negative feedback to a detection voltage (VDET) and thereby, implements close loop control to cause transmission power POUT to be closer to a designated level. On the other hand, when the transmission power (POUT) is out of a measurable range of the detecting circuit (3), the power control section (110) sets a detection voltage feedback ratio (K) to 0 to generate the control voltage (VC) according to open loop control based on a reference voltage VREF.

Abstract: An actuator has an actuating element and an actuating drive with an electromagnet with a coil. An armature, which can be coupled to the actuating element, can move between a first contact surface on the electromagnet and a second contact surface. An initial current or a higher holding current flows through the coil until a time at which the armature plate is reliably in contact with the contact surface of the electromagnet. An operating state of high-speed current reduction is then selected, wherein the opposite polarity of the supply voltage in comparison to the initial current flow is applied to the coil. A holding current then flows through the coil.

Abstract: A controller for an electromagnetic actuator is provided that enables detection of a minute movement of the armature leaving the seating position and carries out pullback operation responsive to such detection. The electromagnetic actuator has a pair of springs acting on opposite directions, and an armature coupled to a mechanical element such as a exhaust/intake valve of an automobile engine. The armature is held in a neutral position given by the springs when the actuator is not activated. The actuator includes a pair of electromagnets for driving the armature between two end positions. The controller having current supplying means for supplying holding current to the electromagnet corresponding to one of the end positions when holding the armature in said one of the end positions.

Abstract: A relay controller intermittently connects a power supply across a relay coil with a controlled duty cycle whenever the relay coil is to generate a magnetic field for opening or closing the relay's contacts. The duty cycle with which the controller connects the power supply across the coil controls limits a steady-state amplitude of current passing through the coil, thereby controlling the intensity of the magnetic field the coil generates.

Abstract: An electronic drive control used for controlling a drive coil of a contactor during holding operation with a pulse-width modulation. The interval time for the pulse-width modulation is temporally changed or the pulse-width ratio is continuously changed. The invention may minimize the holding power in the case of high voltages without the occurrence of problems associated with EMC and without reducing the functional reliability.

Abstract: So that an actuator drive which holds an actuator element for actuating, for example, a charge cycle valve of an internal combustion engine, in a limit position by a coil, can be switched at the correct time into the other limit position, the energization of the coil is switched off a certain time period before the time at which the actuator element is to be released from the limit position. Here, the time period is selected as a function of the supply voltage of the actuator drive and/or of the coil current during the holding in the limit position. It is also possible to adapt the time period.

Abstract: An improved method for controlling the landing velocity of an armature in an electromechanical actuator, such as a fuel injector, fuel pressure regulator, or engine valve actuator is provided. The position and velocity of an armature during a stroke is dynamically estimated by calculating the inductance and rate of change of inductance of the actuator coil in real-time as the armature moves through its stroke, compensating for non-linear permeability and magnetization effects due to changing gap, temperature, magnetic material properties or magnetic architecture, normalizing the calculated inductance value at the end of a stroke (zero gap), and mapping the value of normalized inductance to correspond to an armature position by an algebraic transformation. Inductance may be used directly as a position variable without mapping it to units of position. Rate of change of inductance may be used as a rate variable without mapping it to units of velocity.

Abstract: A drive control circuit for an electromagnetic driving device includes a magnet and a drive coil, which moves due to an electromagnetic force when an electrical current flows therethrough. The drive control circuit may include (1) a drive circuit that feeds an electrical current to the drive coil, the drive circuit including at least one voltage source, and (2) a short-circuit system that short-circuits the drive coil. The short-circuit system releases the short-circuited condition of the drive coil in accordance with an output voltage of the at least one voltage source.

Abstract: An electromagnetic fuel injector is provided with a first coil having a large rate of change in time of magnetomotive force and a second coil having a smaller rate of change in time of magnetomotive force than the first coil. During a valve opening operation at the time of opening the valve, current is passed through at least the first coil, and then current of a smaller current value than in the opening operation is caused to flow so as to hold the valve open, using the first and second coils.

Abstract: A control circuit is provided for use in an electromagnetic device with a coil where the electromagnetic device is actuated with an actuating current and held in an operative condition by a holding current with the holding current being significantly lower in magnitude than the actuating current. The control circuit includes first and second transistors wherein, during a powered mode, the first transistor is disposed in an on state and the second transistor is disposed in an off state, and, during a shorted mode, the first transistor is disposed in an off state and the second transistor is disposed in an on state. Additionally, a power source selectively communicates with the coil, and during a first time interval, the power source communicates with the coil in the powered mode and, during a second time interval, the power source is disconnected from the coil in the shorted mode.

Abstract: An amplifier/power supply for an engine valve actuator includes a pair of switches for operating an actuator coil in several modes from a low voltage power supply. A higher magnitude voltage is regeneratively created using the inductance of the actuator coil and selective actuation of the switches.

Abstract: A method is described for operating a fuel injector for fuel injection systems of internal combustion engines, particularly for the direct injection of fuel into a combustion chamber of an internal combustion engine. The fuel injector has a magnetic coil, an armature acted upon in a closing direction by a resetting spring, and a valve needle, frictionally connected to the armature, for actuating a valve-closure member which, together with a valve-seat surface, forms a sealing seat. The method includes exciting the magnetic coil with a basic current intensity during an opening phase of the fuel injector, shortly before the end of the opening phase, exciting the magnetic coil with a current pulse that is increased compared to the basic current intensity, and, at the end of the opening phase, switching off the current exciting the magnetic coil.

Abstract: A pre-drive circuit for a brushless DC single-phase motor controls a motor rotational speed by driving a drive circuit for the motor. The drive circuit includes four switching elements, namely, two power-supply-side switching elements and two ground-side switching elements connected in an H configuration bridge across a motor coil of the motor. A control voltage above a power supply voltage is required to turn on the two power-supply-side switching elements. The pre-drive circuit to produce a signal for controlling the switching elements is formed of an inexpensive logic circuit. Signals for controlling the two power-supply-side switching elements are amplified to a voltage level above a power supply voltage by 4 V by operational amplifiers. Drive signal input circuits for feeding signals for controlling the two ground-side switching elements to control input terminals of the two ground-side switching elements are formed of mere respective resistors.

Abstract: A fuel injection apparatus including a controller to output an injection time command signal and an opening movement time command signal to command an opening movement time from a closed state to an open state of an electromagnetic fuel injection valve and a control circuit, coupled to the controller, to change an electric current flowing in a coil of the electromagnetic fuel injection valve between when the electromagnetic fuel injection valve is closed and opened. The controller sends both the injection time command signal and the opening movement time command signal through the same signal line to the control circuit.

Abstract: An electromagnetic door lock has an electromagnet and an armature for bonding thereto. One of the electromagnet and the armature is adapted for mounting to a door and the other of the electromagnet and the armature is adapted for mounting to a door frame. A lock controller pulses current to the electromagnet. The pulses have a predetermined width and a predetermined spacing between pulses.

Abstract: An amplifier/power supply for an engine valve actuator includes a pair of switches for operating an actuator coil in several modes from a low voltage power supply. A higher magnitude voltage is regeneratively created using the inductance of the actuator coil and selective actuation of the switches.

Abstract: The device has an electric circuit for generating a first electric current of such a predetermined value as to excite the electromagnet to open the metering valve, and a second electric current of a lower value such as to keep the electromagnet excited; and a timing device for controlling the electric circuit as a function of operating conditions of the engine. The timing device also controls the electric circuit in such a manner as to vary the duration of the first current as a function of the operating temperature of the engine.

Abstract: The target peak current value, where a current value is reduced in conformity to a drop in the voltage of a battery 18 is stored in target peak current storage unit 68. ON-signals are sent from current control circuit 56 to power transistor 50 in response to the injection command pulse coming from engine controller 58 so that current is applied to coil 20. Then, the current flowing to coil 20 is detected by the current detecting resistor 52. Comparator 62 compares this detected current and the target peak current value read from the target peak current storage unit 68 conforming to the voltage of battery 18. If agreement is found between these two values, OFF-signals are sent to power transistor 50 from current control circuit 56 in response to the switching command coming from comparator 62. Then, On/Off signals to effect holding of the coil 20 are sent from current control circuit 56 to power transistor 50. The linearity of the injection volume despite changes in battery voltage can be maintained.

Abstract: With a cylinder direct injection engine in which fuel is injected directly into combustion chambers and air-fuel mixture is guided by an air flow, it is difficult to secure combustion stability under low engine speed and low load conditions such as during idling. Furthermore, there are needs for improvement of emission characteristics and fuel economy in other operation modes as well. An engine according to the invention injects fuel while dividing the same in plural-parts during a compression stroke. The first injection forms a lean air-fuel mixture around an ignition plug, and the second injection makes a flammable air-fuel mixture reach an area around the ignition plug. This ensures efficient stratified combustion and allows improvement in emission and fuel economy performance.

Abstract: In an electromagnetically actuatable device, an electromagnet is driven with a controlled current progression so that the armature of the electromagnet can be actuated at the lowest possible current level while still achieving the most rapid overall increase of the actuating current from zero to maximum amperage. A first portion or range of the current increase is carried out with a steep or jump-like current increasing characteristic. A second portion or range of the current increase is carried out with a more gradual variation of the current. The current levels at the end points of the respective ranges are selected to ensure that the electromagnet is actuated during the second range in which the current varies more gradually. Preferably, two steep or jump-like current increase ranges are respectively provided before and after the second range having the gradual current increase.

Abstract: A method for providing electrical current to a contactor circuit, by providing a power supply circuit having a power supply resistor, the power supply circuit supplies electrical current to the contactor circuit in response to the electrical specifications of the contactor; selecting a value for the power supply resistor in response to the contactor's electrical specifications and requirements of the contactor circuit; and, inserting the selected power supply resistor into the power supply circuit.

Abstract: A fuel injection control system of low cost for a cylinder injection type internal combustion engine, which system is capable of preventing degradation of fuel injection quantity accuracy which may be brought about by disturbances such as change of a battery voltage, change of resistance of a plunger coil of the fuel injection valve (1) and change of the fuel pressure (Fp) acting on the fuel injection valve (1) which may occur in the course of overexcitation driving of the fuel injection valve (1) at a battery voltage, to thereby allow the fuel injection quantity control to be secured for the fuel injection valve (1) over an extended range.