| 摘要 |
<p>A control apparatus for a piezo injector is provided which includes a chopper and a controller. The chopper works to operate in a current increasing mode and a current decreasing mode cyclically to control a stroke of a piezoelectric device. The controller works to operate selectively in a charge mode to charge electrical energy to the piezoelectric device and a discharge mode to discharge the electrical energy from the piezoelectric device. When entering the discharge mode, the controller switches an operation of the chopper from the current increasing mode to the current decreasing mode at the time when the current reaches a given peak value and also switches it from the current decreasing mode to the current increasing mode when the current reaches a given bottom value. The controller determines at least one of the peak value and the bottom value based on a given electrical quantity of state of the piezoelectric device before start of the discharge mode such as the amount of charge saved in the piezoelectric device to discharge the piezoelectric device within a selected period of time.
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