Abstract: A method of calculating the voltage setpoint of a piezoelectric element as a function of a rail pressure is provided, in which a corrected voltage setpoint is formed by, among other adjustments, using a multiplier as a function of a temperature of the piezoelectric element. Additional adjustments for forming the corrected voltage setpoint includes adjusting the setpoint control voltage by multiplication by at least one correction value (multiplier) and/or by addition of at least one correction value (addend).

Abstract: The invention describes a method and an apparatus for detecting a load decrease when driving a piezoelectric element, for example, used as an actuator in a fuel injection system of an internal combustion engine. The method and apparatus are characterized in that an error signal is generated when the piezoelectric element reaches a target voltage more quickly than a predetermined minimum time interval during a charging or discharging operation.

Abstract: A fuel injection system for an internal combustion engine, in particular a diesel engine, having at least two cylinders, the fuel injection system having at least two actuator elements and at least one actuator element being assigned to each cylinder in order to inject fuel into the cylinder, and the fuel injection system having an injection control system for monitoring and/or resolving a conflict in triggering of the actuator elements.

Abstract: The invention describes a method and apparatus for operating a fuel injection system having a piezoelectric element (10, 20, 30, 40, 50 or 60) for controlling the amount of fuel injected into a combustion engine, characterized in that the piezoelectric element (10, 20, 30, 40, 50 or 60) is controlled based upon the charge it is carrying.

Abstract: The invention describes an apparatus and method for detecting a short circuit to a battery voltage when driving a piezoelectric element, for example, used as an actuator in a fuel injection system of an internal combustion engine. The apparatus and method are characterized in that separate switches are used for selecting a piezoelectric element to be operated and for selecting the operation that is to be performed on the piezoelectric element. A short circuit to battery voltage is detected by first activating the switches to select a piezoelectric element. For a predetermined time interval, the invention monitors for abnormal currents flowing in series with the piezoelectric element. If abnormal currents are detected, an error signal is generated indicating a short circuit to battery voltage.

Abstract: The invention describes a method and an apparatus for charging a piezoelectric element of a fuel injection system for, for example, an internal combustion engine. The apparatus is characterized in that the piezoelectric element is activated by an activation voltage having a value set as a function of measured fuel pressure in the fuel injection system.

Abstract: A method for determining the control voltage for a piezoelectric actuator of an injection valve in which at first the pressure in a hydraulic coupler is measured indirectly, before the next injection process. The pressure is measured since the piezoelectric actuator is mechanically coupled to the hydraulic coupler, so that the pressure induces a corresponding piezo voltage in the actuator. This induced voltage is used before the next injection process for correcting the control voltage for the actuator. Too low an induced voltage is valued as a fault for recognizing an intermittent injection operation. The injection valve may be used for a common rail system for fuel injection in a gasoline or diesel engine.

Abstract: The invention describes a fuel injection system comprising a piezoelectric element for controlling an amount of injected fuel, by charging and discharging the piezoelectric element using a driving circuitry, and a current diagnosis unit capable of detecting a fault of a current flowing in the driving circuitry within 10 &mgr;sec of the fault occurring.

Abstract: A method and a device for controlling a controller having a capacitive element. An ohmic resistor is connected in parallel to the capacitive element. The value of the ohmic resistor is determined at certain times, and then the type and/or temperature of the capacitive element is deduced on the basis of the value of the resistor.

Abstract: A method for determining the control voltage for a piezoelectric actuator of an injection valve in which at first the pressure in a hydraulic coupler is measured indirectly, before the next injection process. The pressure is measured since the piezoelectric actuator is mechanically coupled to the hydraulic coupler, so that the pressure induces a corresponding piezo voltage in the actuator. This induced voltage is used before the next injection process for correcting the control voltage for the actuator. Too low an induced voltage is valued as a fault for recognizing an intermittent injection operation. The injection valve may be used for a common rail system for fuel injection in a gasoline or diesel engine.