Control device

A control device for controlling driving of a fuel injection valve having a solenoid coil, the control device comprising:

• a voltage detection unit configured to detect a counter electromotive voltage generated in the solenoid coil in time-series order;
• a differential calculation unit configured to obtain a differential value by differentiating the counter electromotive voltage detected by the voltage detection unit with respect to time;
• a storage unit configured to store time-series data of the differential value;
• a maximum detection unit configured to detect a maximum point when the differential value has changed from an increase to a decrease by retrospectively tracing the time-series data in an opposite direction of a time series;
• and
• a valve closing time detection unit configured to
• execute a determination process of retrospectively tracing the time-series data from the maximum point detected by the maximum detection unit in the opposite direction and scanning whether or not an amount of decrease in the differential value from the maximum point exceeds a predetermined threshold value, and
• detect a maximum time, which is a time of the maximum point, as a valve closing time of the fuel injection valve when there is an event in which the amount of decrease exceeds the predetermined threshold value.