| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of controlling a piezoelectrically operable fuel injector alleviating or removing a noise problem. SOLUTION: This method controls charging and discharging of a piezoelectric actuator for use in a fuel injector having an injection mode and a non-injection mode. The method comprises the steps of: applying a charging current of variable amplitude to the actuator during a charge mode; applying a discharging current of variable amplitude to the actuator during a discharge mode; monitoring the charging current and the discharging current during the charge and discharge modes, respectively; controlling the discharging current and the charging current in response to the monitored current; and comparing the monitored charging and/or discharging current with a selected current waveform and switching the charging and/or discharging current on and off in response to the result of the comparison. Preferably, the selected waveform includes a maximum current waveform and a minimum current waveform, which define maximum and minimum thresholds, respectively, for comparison with the monitored charging and/or discharge current. COPYRIGHT: (C)2007,JPO&INPIT |
