Siemens Aktiengesellschaft

Siemens Aktiengesellschaft Ag

Continental Automotive Gmbh

Martin Hecker

Christian Hoffmann

Richard Pirkl

Hellmut Freudenberg

Hartmut Gerken

Manfred Weigl

Walter Schrod

Dirk Heinitz

Benno Larisch

G&uuml;nther Riedel

In a driving operation, a capacitive actuator is charged from a series circuit of two capacitors having a charging voltage. An actuator voltage established at the actuator is controlled to a prescribed desired value in a course of a subsequent driving operation; the same procedure occurs for further actuators.

Method and device for driving at least one capacitive actuator

Method of driving a capacitive actuator of a fuel injection valve of an internal combustion engine for achieving a constant stroke of the actuator, in which the amounts of energy that are supplied to the actuator are determined in dependence on the fuel pressure acting on the actuator.

Method of driving a capacitive actuator of a fuel injection valve of an internal combustion engine

A method for controlling a capacitive actuator includes the steps of determining an energy applied to an actuator, measuring an actuator voltage present at the actuator, and inferring a functional state of the actuator by using the energy and the actuator voltage. A capacitive actuator is fed energy and the actuator voltage present at the actuator is measured. The energy and the comparison of the actuator voltage with reference values are used to infer a functional state, for example, either faults or correct function of the actuator or injection valve. Furthermore, the actuator voltage is used to infer an actuator stroke. The method is based on actuator characteristics. The invention also includes a circuit for controlling a capacitive actuator having a driving circuit with a main switch, a charging capacitor, a first series circuit including an oscillating coil, an auxiliary switch, and a second series circuit having a discharging switch, a charging switch, and a diode to be connected to the actuator, and a control device having a program and a family of characteristics with actuator characteristics defining characteristic curves, reference values, and correction factors.

Method and apparatus for controlling a capacitive actuator

A control element, in particular a piezoelectrically operated fuel injection valve in an internal combustion engine, is charged, in order to compensate for stochastic reactions in the internal combustion engine, with a constant nominal voltage applied to a series circuit that includes a charge capacitor and a charge reversal capacitor, and it is discharged into the charge reversal capacitor to a prescribed voltage value. The remaining residual charge of the control element is charged into the charge capacitor via a limiter path.

Method and apparatus for driving at least one capacitive control element

A method of diagnosing an actuator includes supplying a predeterminable amount of energy to an actuator through a charge-reversal circuit. Faulty functional statuses of the actuator and its supply lines and/or its drive circuits, short- or long-term interruptions, short-circuits within the actuator or its supply lines, or excessively low capacitance values may be deduced from a discrepancy between reference values and determined variables including actuator voltage, actuator current, and actuator charge. A short-circuit of an electrical connection within the actuator or an electrical connection between the drive circuit and the actuator can be deduced if the actuator voltage is less than a lower voltage value. An interruption in the electrical connection within is the actuator or an electrical connection between the drive circuit and the actuator may be deduced if an actuator peak current is less than a lower current value. An apparatus for performing the method is also provided.

Method and configuration for diagnosis of a capacitive actuator

A capacitive actuator (P), especially for a piezoelectrically operated injection valve for an internal combustion engine, is short-circuited by a discharge switch (M) after an actuation, the controlling input of the discharge switch (M) being connected to the actuator (P) so that the discharge switch (M) in case of a failure of the external control, is automatically rendered conductive by the actuator voltage (U,) and the actuator (P) is therefore automatically discharged.

Discharge circuit for a capacitive actuator

The device drives one or more capacitive actuators with a control circuit. The device has a series circuit with a charging capacitor, a discharging capacitor, an electric coil, and the one or more actuators each with an associated selector switch. A discharging switch has a drain terminal connected to the node point between the two capacitors, and a source terminal connected via decoupling diodes to the drain terminals of the selector switches.

Device and method for driving at least one capacitive actuator

A short circuit between a negative pole GND and a capacitive actuator in a circuit with a charging capacitor, a recharging capacitor, a recharging coil and a selector switch is determined by calculating a value corresponding to the quantity of charge QL flowing off from the recharging capacitor during a charging operation. The quantity of charge is compared with an integral of current i flowing during the charging operation via the selector switch assigned to the actuator. A short circuit of the actuator to the negative pole is diagnosed when the integral is smaller than k*QL (k<1).

Method for diagnosing a short circuit at a capacitive actuator

A method of driving at least one capacitive actuator with a charge voltage. From a charge quantity .DELTA.Q supplied to the actuator and from the actuator voltage U.sub.p applied to the actuator after the charging operation is terminated, the actuator capacitance is calculated by the equation C.sub.p =.DELTA.Q/U.sub.p. From these values, the energy E.sub.actual =0.5*C.sub.p *U.sub.p.sup.2 =0.5*.DELTA.Q*U.sub.p is calculated. The charge voltage is regulated such that the energy actually supplied is equivalent to a specified desired value.

Method of driving at least one capacitive actuator

A capacitive control element is charged with a defined charging voltage Uc. From a stored mapping KF, the instantaneous control element capacitance Cp is determined from the charge voltage Uc and a control element voltage Up. In addition, energy E supplied to the control element is determined from the charge voltage Uc and the control element capacitance Cp. According to a deviation of energy E fed to the control element from a stipulated amount of energy Ev, the charge voltage Uc for a next drive process of the control element is regulated. The same process occurs for additional control elements.

Method and device for driving a capacitive control element

A device for regulating a pressure in a high pressure accumulator of a fuel injection system includes a pressure adjusting element which has a shut-off element and an electromagnetic drive actuating the shut-off element. A first regulating device is connected to the pressure adjusting element and compares a pressure value obtained in the high pressure accumulator with a given setpoint pressure value. A drive signal with a setpoint current value for the electromagnetic drive is determined as a function of the comparison. A second regulating device is connected downstream of the first regulating device for comparing a current value of a current flowing through the electromagnetic drive with the setpoint current value and readjusting the current value in response to a deviation between the current value and the setpoint current value. A method for regulating a pressure in a high pressure accumulator is also provided.

Device and method for regulating a pressure in accumulator injection

A power MOSFET switch is connected in parallel to a capacitive actuator for the purpose of protecting the actuator against over-voltage. The protective power MOSFET switch is rendered conductive by a supplemental circuit when the actuator voltage exceeds a predetermined threshold limit voltage or when the control circuit emits a corresponding signal.

Device and method for driving a capacitive actuator

A device for driving at least one capacitive actuator contains two capacitors C1 and C2 connected in parallel. The two parallel-connected capacitors C1, C2 are charged to an output voltage U.sub.SNT of a voltage source SNT. The actuator is charged with a voltage U.sub.C1+C2 =2*U.sub.SNT by the capacitors, and thereafter discharged into the capacitors, which are again connected in parallel and are subsequently recharged to the output voltage U.sub.SNT of the voltage source SNT.

A device for driving at least one capacitive actuator contains a charge capacitor C1 and a discharge capacitor C2. According to the method, the actuator is charged with a desired voltage U.sub.s by the capacitors C1+C2 connected in series, and is then discharged into the discharge capacitor C2. The charge capacitor is then recharged to a voltage U.sub.C1 =U.sub.s -U.sub.C2 by a voltage source which can be regulated.

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Laimerstadt, Germany

Martin Hecker