Image Number 5 for United States Patent #7576473.
A method of operating an injector having an injector valve needle and a piezoelectric actuator for controlling movement of the injector valve needle, the method comprising reducing the voltage across the actuator at a first rate (RT1) in order to initiate an initial injection, increasing the voltage across the actuator in order to terminate the injection, and once the initial injection has terminated and before a subsequent injection is initiated, reducing the voltage across the actuator at a second rate (RT2; RT3), which is lower than the first rate (RT1), so as to de-energise the actuator but without initiating an injection. The invention ensures the injector spends a significantly reduced period of its life with a high voltage across its actuator.
|
