| 摘要 |
A method for controlling charging and discharging of a piezoelectric actuator for use in a fuel injector having an inject mode ( 12 ) and a non-inject mode ( 16 ); comprises applying a charging current of variable amplitude to the actuator during a charge mode ( 14 ), wherein the amplitude of the charging current varies with a first PWM frequency, and applying a discharging current of variable amplitude to the actuator during a discharge mode ( 10 ), wherein the amplitude of the discharging current varies with a second PWM frequency. The charging current and/or the discharging current is monitored during the charge and discharge modes ( 10, 14 ), respectively, and the discharging current and/or the charging current is controlled in response to the monitored current. The first and/or second PWM frequency is varied throughout the discharge mode ( 10 ) and/or the charge mode ( 14 ), respectively, so as to suppress resonance modes within the actuator.
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