Abstract: A method for controlling a piezoelectric actuator which displaces a control element of an injection valve includes the step of charging the actuator until a start voltage is reached. Subsequently, the actuator is discharged until a partial lifting voltage, which is maintained during a holding time, is reached. In the final step, the actuator is discharged until an off-load voltage is reached and a parameter which is dependent on the partial lifting voltage is used as a control variable. A desired value for the control variable is determined and the actuator is controlled in such a manner that the desired value of the control variable is maintained.

Abstract: A piezo-actuator is actuated in a first operating mode (B1) by pulsed supply of a first electrical variable for charging or discharging of the piezo-actuator taking into account at least one actuation parameter (P) for the piezo-actuator. The piezo-actuator is actuated in a second operating mode (B2) by non-pulsed introduction of the first electrical variable for charging or discharging of the piezo-actuator, to be precise with the first electrical variable having a predetermined profile which is substantially independent of any load change on the piezo-actuator (1). A profile of a second electrical variable of the piezo-actuator is recorded during at least one measurement time period while the predetermined profile of the first electrical variable is being applied. The at least one actuation parameter (P) of the piezo-actuator is determined as a function of the recorded profile of the second electrical variable.

Abstract: A method for injecting a fluid, in particular a fuel, performs the following steps: A nozzle (1) which can be actuated by a piezo element (5) is provided. A current pulse (12a) is supplied to the piezo element (5). The capacity (16) of the piezo element (5) is recorded at the time when the current pulse (12a) is supplied. An actual characteristic curve of the injection is recorded based on the capacity (16). The current pulse (12a) is regulated in order to optimize the injection based on the actual characteristic curve of the injection.

Abstract: An injection system for injecting fuel has: a housing for containing the fuel, with a first and second aperture, a piezo actuator having a first and second face plate aperture, a controllable piezo stack arranged between the face and base plate, a sealed casing laterally surrounding at least the piezo stack and arranged between the face and base plate and a transmission means arranged in an actuator interior space having a fluid, a first contact device guided through the first aperture and face plate aperture, a second contact device guided through the second aperture and face plate aperture, a first sealing device surrounding the contact device near the apertures and providing a seal between the housing interior and exterior space and a second sealing device surrounding the contact devices near the face plate apertures and providing a seal between the housing interior space and the actuator interior space.

Abstract: An piezo actuator loading signal is determined and generated according to an output value and a pilot control value which depends on at least one operational parameter. The loading signal causes that a valve member moves into a valve seat. A first value characteristic of the electric power fed to the actuator when the valve member hits the valve seat is determined while a second value characteristic of the energy delivered to the actuator is determined when the loading process of the actuator has been completed. A real value characteristic of a sealing force with which the valve member is pressed onto the valve seat is determined according to the first and second value. The real value and a predefined setpoint value are fed to the controller which accordingly adjusts a pilot control value assignment instruction which is used for determining the pilot control value if a predefined condition is met.

Abstract: A valve has a piezo actuator, a valve element, a valve body and a valve seat. At a predeterminable point in time, the valve element is controlled by a discharging process of the piezo actuator from a position in which it rests against the valve seat to a predetermined position located at a distance from the valve seat. The discharging process is divided into a first discharging period during which a predetermined first amount of electrical energy is discharged from the piezo actuator, a subsequent holding time period during which the piezo actuator is not controlled, and a subsequent second discharging period during which a predetermined second amount of electrical energy is discharged. The holding time duration and/or the first discharging period are/is adapted according to the course of a value that is not characteristic of the oscillation behavior of the piezo actuator during the holding time period.

Abstract: A valve has a piezoelectric actuator with a valve element, a valve body and a valve seat. In order to control the valve, the valve element is moved into the valve seat from a position remote from the valve seat by means of a charging process at a prescribable first time. A first value is determined being characteristic of the electrical power supplied to the piezoelectric actuator when the valve element meets the valve seat. A second value is determined being characteristic of the electrical power supplied to the piezoelectric actuator when the charging process of the piezoelectric actuator is concluded. An actual difference value between the second value and the first value is determined. A difference between a setpoint difference value and the actual difference value is supplied to a controller. An actuating signal for charging the piezoelectric actuator is determined as a function of the actuating variable.

Abstract: When a drive command (S*) is input by a control circuit (3), a drive signal (S) can be emitted to a piezoelectric actuator (Pi) by a drive circuit (1), with the result that the piezoelectric actuator (Pi) is changed over from a zero position to a drive position. When a correction command (I1*, I2*) is input by the control circuit (3), a correction signal (I1, I2) can be emitted to the piezoelectric actuator (Pi) by a correction circuit (2), with the result that the piezoelectric actuator (Pi) is changed over from the zero position to a correction position. The input of the drive command (S*) and the input of the correction command (I1*, I2*) are interlocked with respect to one another.

Abstract: A valve has a piezoelectric actuator with a valve element, a valve body and a valve seat. In order to control the valve, the valve element is moved into the valve seat from a position remote from the valve seat by means of a charging process at a prescribable first time. A first value is determined being characteristic of the electrical power supplied to the piezoelectric actuator when the valve element meets the valve seat. A second value is determined being characteristic of the electrical power supplied to the piezoelectric actuator when the charging process of the piezoelectric actuator is concluded. An actual difference value between the second value and the first value is determined. A difference between a setpoint difference value and the actual difference value is supplied to a controller. An actuating signal for charging the piezoelectric actuator is determined as a function of the actuating variable.

Abstract: The current guided to the piezo actuator and the voltage which is consequently established thereon is used for calculating with the help of a non-linear actuator model, the characteristics of the longitudinal variations (s) and the force (F) exerted by the actuator (F), and variables therefrom or the derived variables (dF/dt) therefrom determine the beginning of the opening (tA) of a servovalve and the duration of injection (D).

Abstract: When a drive command (S*) is input by a control circuit (3), a drive signal (S) can be emitted to a piezoelectric actuator (Pi) by a drive circuit (1), with the result that the piezoelectric actuator (Pi) is changed over from a zero position to a drive position. When a correction command (I1*, I2*) is input by the control circuit (3), a correction signal (I1, I2) can be emitted to the piezoelectric actuator (Pi) by a correction circuit (2), with the result that the piezoelectric actuator (Pi) is changed over from the zero position to a correction position. The input of the drive command (S*) and the input of the correction command (I1*, I2*) are interlocked with respect to one another.

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: The current guided to the piezo actuator and the voltage which is consequently established thereon is used for calculating with the help of a non-linear actuator model, the characteristics of the longitudinal variations (s) and the force (F) exerted by the actuator (F), and variables therefrom or the derived variables (dF/dt) therefrom determine the beginning of the opening (tA) of a servovalve and the duration of injection (D).

Abstract: A method for setting a predetermined travel of an actuator (1), in particular a piezo-electric actuator (1) for an injector of an injection system is disclosed. According to said method, a first electric state variable (Q) of the actuator (1), which determines the travel of the actuator (1), is set. Said first electric state variable (Q) is set in accordance with the temperature (TAKTOR) of the actuator (1), to avoid temperature-induced fluctuations of the actuator travel.

Abstract: A method for setting a predetermined travel of an actuator (1), in particular a piezo-electric actuator (1) for an injector of an injection system is disclosed. According to said method, a first electric state variable (Q) of the actuator (1), which determines the travel of the actuator (1), is set. Said first electric state variable (Q) is set in accordance with the temperature (TAKTOR) of the actuator (1), to avoid temperature-induced fluctuations of the actuator travel.

Abstract: 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.

Abstract: 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.

Abstract: A method and a device for charging a capacitive actuator are described. The capacitive actuator, in particular for a fuel injection valve of an internal combustion engine, is charged or discharged with different charging and discharging times. In order to shorten the charging time, the capacitance of the recharging capacitor which is dimensioned for a maximum charging time is reduced at a predefined time during the charging process. Two exemplary embodiments of a device for carrying out the method are explained in more detail.

Abstract: 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.

Abstract: 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.