Patent ID: 7626315

Claim:
A driving apparatus for a piezo-injector including a piezoelectric element, the apparatus comprising: a driving circuit for controlling electrical charging and discharging of the piezoelectric element corresponding to expansion and contraction of the piezoelectric element; a setting circuit that is configured to set, in control of at least one of (i) expansion and (ii) contraction in each fuel injection operation of the piezoelectric element, the rate of change in the electrical charge state after a start period of the control to a value larger than that in the start period, and the rate of change in the electrical charge state amounts in an end period preceding an end of the control to a value smaller than that in a period following the start period, the electrical charge state being variable with at least a voltage of the piezoelectric element; and an operation circuit that operates the driving circuit rates of charging and discharging to match the set rates of change.