Abstract: The invention describes an apparatus and a method for charging or discharging a piezoelectric element of a system, e.g., for a fuel injection system. The method and apparatus are characterized in that the current of a system is regulated as a function of a time characteristic and an event characteristic to achieve an effective low absolute average current.

Abstract: The invention describes a method and an apparatus for charging 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 the piezoelectric element is activated by an activation voltage having a value set as a function of manufacturing characteristics of the particular piezoelectric element and based upon, for example, a correction value for injected fuel volume.

Abstract: A method and an apparatus for controlling system parameters, in particular for controlling the voltage applied to piezoelectric elements (10, 20, 30, 40, 50, 60) within a circuit (A) for charging and discharging piezoelectric elements (10, 20, 30, 40, 50, 60) are described. The method is characterized by modifying at least one control parameter for the control of a system parameter, in particular a target voltage for the voltage applied to a piezoelectric element (10, 20, 30, 40, 50, 60), in view of at least one systematic error occurring during a first control procedure of the system parameter to obtain a corrected control parameter for a second and/or a further control of the system parameter. The apparatus is particularly eligible for use with the inventive method.

Abstract: A Method and an apparatus for providing control parameters to or within a control system for controlling a fuel injection system are described. The method is characterized in that a plurality of control parameters is transmitted to storage means (810) within the control system by transmission means (850). The transmitted control parameters are stored within the storage means (810). Selection parameters are transmitted to selection means (800) within the control system by transmission means (840). Stored control parameters are selected in accordance with transmitted selection parameters by the selection means (800). And the selected parameters are utilized for controlling elements within the control system. The apparatus is in particular eligible for usage with a inventive method and is characterized in that a control unit (D) and an activation IC (E) are connected to each other by transmission means (840, 850). Storage means (810) are implemented in the activation IC (E).

Abstract: Fuel injection system comprising a piezoelectric element for controlling the amount of injected fuel and further comprising a control unit for determination of a possible fault of the piezoelectric element or of an electric circuitry driving the piezoelectric element based upon a value related to the capacitance of the piezoelectric element.

Abstract: A method and a device are described for detecting a fault current across a piezoelectric actuator (5) of an injector or its high voltage supply lead (6, 6a). Because the fault current upon contact with a person, for example, is relatively small compared to the useful current that charges or discharges the actuator, direct measurement of the current is not reliable. Therefore, it is suggested that, during the injection or in an injection pause, when the piezoelectric actuator (5) is charged, the voltage variation or a change in voltage (dU) be measured and the difference be compared to a predefined threshold value (S). When the threshold value (S) is exceeded, a fault message is produced, the voltage source is shut off, and/or the piezoelectric actuator (5) is discharged. The measured fault can be weighted using a counting algorithm. The method thus provides maximum protection upon contact, in particular for service personnel.

Abstract: Online optimization of injection systems having piezoelectric elements which are used, for example, as actuators in a fuel injection system of an internal combustion engine, wherein the piezoelectric element is activated by an activation voltage having a value set as a function of operating characteristics of the particular piezoelectric element, and based upon, for example, a correction value for injected fuel volume.

Abstract: The invention describes a method and an apparatus for driving fuel injectors divided into a plurality of injector banks, each bank containing at least one piezoelectric element, each bank being selected for charging or discharging by a bank-selection switch. The apparatus is characterized in that a bank selection switch includes a triac with a triac drive circuit.

Abstract: The invention describes a method and an apparatus for a fuel injection system with a piezoelectric element for controlling the amount of injected fuel by charging and/or discharging the piezoelectric element, wherein the fuel injection system comprises a current flow controller for charging and/or discharging the piezoelectric element based upon the gradient of a voltage across the piezoelectric element due to a charge the piezoelectric element is carrying.

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: 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 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: A method and a device are described for detecting a fault current across a piezoelectric actuator of an injector or its high voltage supply lead. Because the fault current upon contact with a person, for example, is relatively small compared to the useful current that charges or discharges the actuator, direct measurement of the current is not reliable. Therefore, it is suggested that, during the injection or in an injection pause, when the piezoelectric actuator is charged, the voltage variation or a change in voltage be measured and the difference be compared to a predefined threshold value. When the threshold value is exceeded, a fault message is produced, the voltage source is shut off, and/or the piezoelectric actuator is discharged. The measured fault can be weighted using a counting algorithm. The method thus provides maximum protection upon contact, in particular for service personnel.

Abstract: Online optimization of injection systems having piezoelectric elements which are used, for example, as actuators in a fuel injection system of an internal combustion engine, wherein the piezoelectric element is activated by an activation voltage having a value set as a function of operating characteristics of the particular piezoelectric element, and based upon, for example, a correction value for injected fuel volume.

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.