Injection control device

An injection control device configured to control opening and closing of a plurality of fuel injection valves to inject fuel to an internal combustion engine, the injection control device comprising:

• an energization instruction switch configured to switch a plurality of energization instruction signals ON and OFF to instruct energization of the plurality of fuel injection valves;
• a first cylinder designation switch configured to designate one of the plurality of energization instruction signals, which correspond to the plurality of fuel injection valves respectively, to designate a valve closing detection cylinder;
• a valve closing detection unit configured to monitor a plurality of downstream voltages of the fuel injection valve to detect occurrence of an inflection point in change of the plurality of downstream voltages and to detect valve closing;
• a second cylinder designation switch configured to designate one of the plurality of downstream voltages, which correspond to the plurality of fuel injection valves respectively, and to designate the valve closing detection cylinder;
• a stage number designation unit configured to designate a valve closing detection stage number to a plurality of injections of the valve closing detection cylinder;
• a valve closing time measuring unit configured to measure a valve closing time, which is from a switching timing at which the energization instruction signal is switched from ON to OFF to a valve closing detection timing at which the valve closing detection unit detects the valve closing, for injection of the valve closing detection stage number among the plurality of injections of the valve closing detection cylinder;
• and
• a valve closing time learning unit configured to learn the valve closing time measured by the valve closing time measuring unit.