| 摘要 |
<p>A charge control unit controls electricity charged to a piezo element (Pa, Pb), which is for actuating a backpressure control valve (66) so as to control backpressure applied to a valve element (54) for a fuel injection valve. The backpressure control valve (66) is configured to start to decrease the backpressure to actuate the valve element (54) to open an injection port (57) of the fuel injection valve when voltage of the electricity exceeds a threshold (Vth). A charge unit (30, 1) increases the voltage by repeating increasing and decreasing a drive current, which is supplied to the piezo element (Pa, Pb), for multiple times for charging the piezo element (Pa, Pb). A switching unit (10, 18) alternates the increasing and the decreasing such that the voltage exceeds the threshold (Vth) in an intermediate period in a middle of a specific increasing period among multiple increasing periods, in each of which the drive current increases.</p> |
