Matt,

Sascha has good insight as to the fluid dynamics issues - fluid modes.

Another company I worked for designed a fuel injector driver that had variable rise, dwell and fall adjustments for drive injector coil voltage and, consequently, current. The waveform was close loop controlled via a PWM circuit. A PID was used to control while the basic injector opening (based on engine speed), while duration (injector closing) was a function of engine load.

In addition to control of the coil voltage, there was a dc to dc converter that supplied the appropriate high voltage source from a 24 VDC or 110 VDC (as appropriate) nominal source.

Injector bounce can be a problem. Bosch has a chip (and a patent) that uses back emf to sense solenoid plunger position and control the energy applied to an injector coil. There are some programmable parameters to the chip. This was too many years ago and too much water under the bridge to remember the details.

Bruce