Patent ID: 7778765

Claim:
A fuel injector control apparatus for an internal combustion engine which includes a fuel injector for injecting fuel directly into a combustion chamber of the internal combustion engine, and a fuel pressure sensor for detecting a pressure of the fuel supplied to the fuel injector; wherein: the control apparatus is adapted to control the fuel injector for driving thereof by calculating, from an operational state of the internal combustion engine and fuel pressure detected by the fuel pressure sensor, pulse width of a pulse signal which drives a valve of the injector; the control apparatus comprises a driving signal waveform command unit; after a valve-opening command has turned on and a high valve-opening current for opening the fuel injector valve has been supplied from a high-voltage source to the fuel injector, the command unit discharges the current and supplies from a low-voltage source a hold current Ih 2 to allow the fuel injector to maintain the valve-open state; and during a time from supply of the valve-opening current to arrival at a value of the hold current Ih 2 , after an elapse of a previously assigned rapid-discharge starting time Tsy from the turn-on of the valve-opening command, the command unit rapidly discharges the current until the hold current Ih 2 has been reached.