Robert Boschgmbh

Matthias Mrosik

Udo Schulz

Volker Pitzal

Johannes-J&ouml;rg Rueger

Marco Gangi

Friedrich Boecking

Johannes-Joerg Rueger

Eduard Moser

Bertram Sugg

Michael Schueller

A method and device for testing a fuel metering system. A control unit checks the injector contacts during the initialization phase prior to starting up the fuel metering system. For the test, the injectors are activated by the control unit, and the current values and/or voltage values are evaluated to detect errors. The control unit controls the fuel metering process during operation.

Method and device for testing a fuel metering system

A method and an apparatus for controlling system parameters, in particular for controlling the voltage applied to piezoelectric elements ( ) within a circuit (A) for charging and discharging piezoelectric elements ( ) 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 ( ), 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.

Method and apparatus for controlling system parameters

A method is proposed for diagnosing the drive voltage for a piezoelectric actuator of an injector, in which the drive voltage is measured for the individual phases of the injection procedure. With respect to each control phase, a corresponding tolerance band is provided, which is set using the setpoint value of the drive voltage. The tolerance ranges are established as a function of operating and/or environmental conditions. If, for the individual drive cycles, the corresponding tolerance ranges are not reached, then, in response to repeated measurement, these erroneous measurements are counted. When a preestablished number for the erroneous measurements is exceeded, then an ongoing error is diagnosed. If, after a certain time, the number is not exceeded, then the counter is reset. In the case of an error, the error storage unit can be reset using a maintenance plug-in device during maintenance.

Method for the diagnosis of the voltage control for a piezoelectric actuator of an injection valve

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.

Fuel injection system

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 (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 ( ) 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.

Method and device for detecting a fault current across a piezoelectric actuator of an injector or its high voltage supply lead

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.

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Stuttgart, Germany

Matthias Mrosik