Patent application number | Description | Published |
20100059021 | FUEL INJECTION SYSTEM AND METHOD FOR ASCERTAINING A NEEDLE STROKE STOP IN A FUEL INJECTOR - In fuel injection system having at least one fuel injector and a control unit for triggering the injector, each injector has a piezoelectric actuator, a nozzle element having at least one nozzle opening and at least one movable nozzle needle for selectively closing and opening the at least one nozzle opening, a hydraulic coupling element, which is connected between the piezoelectric actuator and the nozzle needle, and at least one stroke stop, against which the nozzle needle rests in its completely open and/or completely closed position. To be better able to ascertain when the stroke stop is reached in such injectors, the needle stroke stop is ascertained during an energization pause of the piezoelectric actuator by analyzing a voltage signal applied to the piezoelectric actuator. Oscillations of the voltage signal during the energization pause are preferably analyzed. To this end, regression lines are drawn through the voltage characteristic, a correlation coefficient of the regression lines to the voltage characteristic is ascertained and a needle stroke stop is detected on the basis of the correlation coefficient. | 03-11-2010 |
20110180046 | METHOD FOR OPERATING A FUEL INJECTOR - A method is for operating a fuel injector, in particular of an internal combustion engine of a motor vehicle, the fuel injector including a piezoelectric actuator for driving a valve needle, which is connected, preferably hydraulically, to the actuator, and the control voltage of the piezoelectric actuator being analyzed to infer an operating state of the fuel injector. According to this method, the second time derivative of the control voltage and/or a variable depending on the second time derivative of the control voltage is/are analyzed. | 07-28-2011 |
20120013325 | METHOD FOR DETERMINING A NEEDLING CLOSING IN A PIEZOINJECTOR - In a method for determining a needle closing of a valve needle that is driven by a piezoactuator, a signal of a voltage present at the piezoactuator is measured and the needle closing is detected from a curve of the signal. | 01-19-2012 |