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: In a method and a device for dynamically determining a segment for an angular spread, fuel is injected into an internal combustion engine and the useful injection range (IRu) and/or the relative position of the segment comprising the angular spread, in which a fuel injection can be carried out especially during a multiple injection, are variable. A corresponding adaptation of the useful injection range (IRu) can advantageously trigger a subsequent injection impulse, as required, for example, for a regeneration module of a diesel particle filter. The adaptation is carried out according to an operating parameter, for example according to the rotational speed gradient.

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: 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: The invention relates to a method and a device for offsetting bounce effects in a piezo-actuated injection system of an internal combustion engine using a control valve actuated by a piezoelectric actuator. The inventive method comprises the following steps: detecting an actual bounce behavior of the control valve, and determining and offsetting a deviation between the actual bounce behavior and a desired bounce behavior of the control valve, thereby generating an actuation information for the control valve which influences a speed characteristic of a needle of the control valve. The invention also relates to a device for carrying out the inventive method.

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 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: In a method for determining the closure time for a valve, operated by a piezoelectric actuator, in order to record the closing time, the voltage at the piezoelectric actuator is recorded and the time is recorded at which the voltage has a maximum difference value from a comparison curve. The difference curve is generated between a start and an end point for a measured curve, having the voltage values applied to the piezoelectric actuator. A precise determination of the closing time can thus be carried out.

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 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: In a method for determining the closure time for a valve, operated by a piezoelectric actuator, in order to record the closing time, the voltage at the piezoelectric actuator is recorded and the time is recorded at which the voltage has a maximum difference value from a comparison curve. The difference curve is generated between a start and an end point for a measured curve, having the voltage values applied to the piezoelectric actuator. A precise determination of the closing time can thus be carried out.

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: 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: A method and a control system for applying defined clamping forces in a brake that is electrically operable by an actuator and includes a first friction surface and a second friction surface in between which a clearance is allowed, wherein the application the first friction surface against the second friction surface is determined, and wherein a static correlation exists between its actuating travel or, respectively, the actuator position and clamping force, and wherein values of the clamping force as well as of the actuator position measured by a clamping force sensor and a position sensor are determined. To optimize the time-consuming initialization of the sensors used to determine the clamping force and the actuator position and, respectively, to take into account the non-linear rigidity characteristic of the system the control concept, the present invention discloses having the correlation described by a mathematical model whose parameters are determined during actuation.

Abstract: The present invention relates to a method and a control system for applying defined clamping forces in a brake that is electrically operable by means of an actuator and includes a first friction surface (friction lining) and a second friction surface (brake disc) in between which a clearance is allowed, wherein the application of the first friction surface against the second friction surface is determined, and wherein a static correlation exists between its actuating travel or, respectively, the actuator position (jactual) and the clamping force (Factual) , and wherein values (Fmeas, jmeas) of the clamping force as well as of the actuator position measured by means of a clamping force sensor and a position sensor are determined.