| 摘要 |
<p>A method of operating a fuel injector (12a,12b) including a piezoelectric actuator (11) having a stack of piezoelectric elements (9), and wherein in use the injector communicates with a fuel rail, the method comprising: (a) applying a discharge current (I DISCHARGE ) to the actuator (11) for a discharge period (T0 to T1) so as to discharge the stack from a first differential voltage level (V0) across the stack to a second differential voltage level (V1/V2) across the stack; (b) maintaining the second differential voltage level for a period of time (T1 to T2); and (c) applying a charge current (I CHARGE ) to the actuator (11) for a charge period (T2 to T3; T2 to T3') so as to charge the stack from the second differential voltage level to a third differential voltage level (V3); wherein the third differential voltage level is selected in dependence on at least two engine parameters, the at least two engine parameters selected from: rail pressure (P); the electric pulse time (T on ); and the piezoelectric stack temperature (Temp).</p> |
