Image Number 6 for United States Patent #6923161.
A fuel injector control system and method provides precise fuel injection timing while eliminating the need for a voltage regulator by estimating or predicting ramp times between voltage application and actual fuel injection. In one embodiment, an estimated ramp time injection is calculated from a measured voltage and is used to delay or advance application of the voltage on the coil so that the load current reaches a desired current level at a desired injection start time. In another embodiment, an actual ramp time for a given injection is measured and used to predict future ramp times. A current regulator prevents excessive emissions from being generated when controlling the load current.