Abstract: A current source contains a first switching element which is provided with a control input and is embodied and arranged in such a way that an output flow on an output side of a current source can be adjusted according to a control signal at the control input. The current source also contains a reference resistance that is electrically coupled to a first switching element in such a way that a potential difference above the reference resistance represents the output flow. The adjustment signal of a regulator unit depends on the voltage difference above the reference resistance, is the control signal of the first switching element, and contains a time function element which limits a first value of the output flow to a maximum duration and then reduces the value of the output flow.

Abstract: In a method for calibration, a piezo-actuator (1) is actuated in a motor vehicle by a control circuit and an output stage. The piezo actuator is, in particular, part of the injection valve. The piezo-actuator (1) is subjected to an electric calibration pulse that is in the high-level signal range thereof when the control circuit and the output stage are in operation, the frequency thereof being modified over time. The associated electric impendence curve over the frequency is determined and evaluated during the calibration pulse. The output stage is controlled by the control circuit in such a manner that the calibration pulse is generated.

Abstract: A tendency of the controlled load to oscillate when controlling a capacitive load can be avoided according to a piezo actuator for an injection valve of an internal combustion engine, having charging and discharging processes for charging and discharging the capacitive load by means of a load current, each loading process being effected by chronological partial load current pulses according to chronological partial charging capacity pulses (p1, p2, . . . pn), wherein the envelope (E) of the partial charging capacity pulses (p1, p2, . . . pn), during the loading process, increases in a strictly monotonous manner in an initial phase, and the slope of the envelope decreases in a monotonous manner.

Abstract: A circuit arrangement for operating at least one inductive load, for example a solenoid of a fuel injection valve, is configured to feed back electrical energy into a storage capacitor in a freewheeling phase after driving the load. In order to avoid an unwanted voltage increase on the capacitor, the circuit arrangement includes a DC/DC converter with the output-side storage capacitor to provide an operating voltage for the load. A drivable circuit arrangement optionally connects the load to the capacitor, and a freewheeling diode arrangement feeds back electrical energy into the capacitor after the circuit arrangement has been switched off. A protection circuit, which is connected in parallel with the capacitor, provides a current path for limiting the charging voltage on the capacitor in the event of an excessively high voltage on the capacitor.

Abstract: The invention relates to a monitoring method for an actuator (CP), in particular for a piezoelectric actuator (CP) on an injection valve for an internal combustion engine, comprising the following steps: measurement of the electrical current (iR1), flowing through the actuator (CP) in an actuator circuit, measurement of the electrical current (iR3), flowing before or after the actuator (CP) in the actuator circuit, comparison of both measured currents (iR1, iR2) for recognition of a fault and generation of a diagnostic signal (DIAG), displaying the fault, depending on the comparison. According to the invention, the diagnostic signal (DIAG) can take on at least three different values for the representation of an earth short-circuit, a voltage short-circuit and an error-free status depending on the comparison of the measured currents. The invention further relates to a corresponding driver circuit.

Abstract: A current source contains a first switching element which is provided with a control input and is embodied and arranged in such a way that an output flow on an output side of a current source can be adjusted according to a control signal at the control input. The current source also contains a reference resistance that is electrically coupled to a first switching element in such a way that a potential difference above the reference resistance represents the output flow. The adjustment signal of a regulator unit depends on the voltage difference above the reference resistance, is the control signal of the first switching element, and contains a time function element which limits a first value of the output flow to a maximum duration and then reduces the value of the output flow.

Abstract: A tendency of the controlled load to oscillate when controlling a capacitive load can be avoided according to a piezo actuator for an injection valve of an internal combustion engine, having charging and discharging processes for charging and discharging the capacitive load by means of a load current, each loading process being effected by chronological partial load current pulses according to chronological partial charging capacity pulses (p1, p2, . . . pn), wherein the envelope (E) of the partial charging capacity pulses (p1, p2, . . . pn), during the loading process, increases in a strictly monotonous manner in an initial phase, and the slope of the envelope decreases in a monotonous manner.

Abstract: A method for the electric control of an actuator, especially a piezoelectric actuator of an injection system comprises the following steps: charging the actuator; waiting during a specific period of time (D1, D2) and discharging the actuator after the expiration of the period of time (D1, D2). The period of time (D1, D2) is variably determined in order to compensate the quantization steps.

Abstract: Defective actuators in an internal combustion engine with at least one cylinder are detected. A mean value, in particular the arithmetic mean value, determines a measurement variable of all the actuators of a given type present on the cylinders. The measurement variable depends on at least one parameter. In a further step, a deviation is formed which is independent of the parameter. This ensures that the deviation across the entire parameter range remains constant. In a further step, the limit values, in particular the upper and lower limit values, are formed, the limit values being dependent on the deviation and on the mean value formed above. If an individual value of the measurement variable exceeds one of the two limit values, the method according to the invention detects this actuator as faulty and/or defective.

Abstract: In an adjustment method and an adjustment device for an actuator of a valve, in particular for a piezoelectric actuator of an injection valve for an internal combustion engine, wherein the actuator is charged to various charge states, following a given control procedure, which each correspond to a position of the valve. The control procedure is regulated in dependence on a regulation parameter. The regulation parameter describes the charge state of the actuator and/or the valve position and, in addition, an external measured parameter, namely the pressure on the valve.

Abstract: A device for controlling a piezoelectric actuator (Cp), in particular for a fuel-injection valve of an internal combustion engine, comprises an energy source (EQ), which supplies the actuator (Cp) with energy (E0), whereby the extension of the piezoelectric actuator (Cp) corresponds with a predetermined response to changes in temperature. A compensation capacitor (C0) is connected in parallel to the piezoelectric actuator (Cp). The capacitance of said capacitor is calculated in such a way that the extension (Cp) of the actuator remains approximately constant over the temperature range, when supplied with a constant amount of energy (E0) by the energy source (EQ).

Abstract: The invention relates to a monitoring method for an actuator (CP), in particular for a piezoelectric actuator (CP) on an injection valve for an internal combustion engine, comprising the following steps: measurement of the electrical current (iR1), flowing through the actuator (CP) in an actuator circuit, measurement of the electrical current (iR3), flowing before or after the actuator (CP) in the actuator circuit, comparison of both measured currents (iR1, iR2) for recognition of a fault and generation of a diagnostic signal (DIAG), displaying the fault, depending on the comparison. According to the invention, the diagnostic signal (DIAG) can take on at least three different values for the representation of an earth short-circuit, a voltage short-circuit and an error-free status depending on the comparison of the measured currents. The invention further relates to a corresponding driver circuit.

Abstract: Defective actuators in an internal combustion engine with at least one cylinder are detected. A mean value, in particular the arithmetic mean value, determines a measurement variable of all the actuators of a given type present on the cylinders. The measurement variable depends on at least one parameter. In a further step, a deviation is formed which is independent of the parameter. This ensures that the deviation across the entire parameter range remains constant. In a further step, the limit values, in particular the upper and lower limit values, are formed, the limit values being dependent on the deviation and on the mean value formed above. If an individual value of the measurement variable exceeds one of the two limit values, the method according to the invention detects this actuator as faulty and/or defective.

Abstract: A method and a device for measuring the period of time which the valve needle (50) of a control valve (21) of a piezo pump nozzle unit requires to move from a first end position (64) into a second end position (65) is determined as a function of the voltage (u (t)) which is applied to the control valve (21) and/or the current (i (t)) which is applied. The actuation signal is generated at a time at which it is ensured that the pressure in the control valve (21) corresponds largely to the pressure of the fuel low-pressure region (31) during the measurement.

Abstract: A method for the electric control of an actuator, especially a piezoelectric actuator of an injection system comprises the following steps: charging the actuator; waiting during a specific period of time (D1, D2) and discharging the actuator after the expiration of the period of time (D1, D2). The period of time (D1, D2) is variably determined in order to compensate the quantization steps.

Abstract: A device for controlling a piezoelectric actuator (Cp), in particular for a fuel-injection valve of an internal combustion engine, comprises an energy source (EQ), which supplies the actuator (Cp) with energy (E0), whereby the extension of the piezoelectric actuator (Cp) corresponds with a predetermined response to changes in temperature. A compensation capacitor (C0) is connected in parallel to the piezoelectric actuator (Cp). The capacitance of said capacitor is calculated in such a way that the extension (Cp) of the actuator remains approximately constant over the temperature range, when supplied with a constant amount of energy (E0) by the energy source (EQ).

Abstract: A capacitive actuator element, in particular of a fuel injection valve of an internal combustion engine, is charged with different charging times. In order to shorten the charging time, the charging oscillatory circuit is switched over to a freewheeling circuit, and in order to prolong the charging time, switching back from the freewheeling circuit to the charging circuit takes place, it being possible to switch backwards and forwards repeatedly between the freewheeling circuit and charging circuit.

Abstract: A capacitive actuator element, in particular of a fuel injection valve of an internal combustion engine, is charged with different charging times. In order to shorten the charging time, the charging oscillatory circuit is switched over to a freewheeling circuit, and in order to prolong the charging time, switching back from the freewheeling circuit to the charging circuit takes place, it being possible to switch backwards and forwards repeatedly between the freewheeling circuit and charging circuit.

Abstract: A capacitive actuator is charged from a charged energy storage capacitor via a transformer by applying pulse width-modulated control signals with a specific voltage, frequency and duty ratio to a charging switch disposed on the primary side. The duration, magnitude and waveform of the actuator voltage can in this case be chosen as required. The actuator can be discharged in the same way.

Abstract: A capacitive actuator is charged from a charged energy storage capacitor via a transformer by applying pulse width-modulated control signals with a specific voltage, frequency and duty ratio to a charging switch disposed on the primary side. The duration, magnitude and waveform of the actuator voltage can in this case be chosen as required. The actuator can be discharged in the same way.