Timing control . The start and end of the injection process is electronically controlled. The internal HEUI plunger does not move until the solenoid is energized. This means the movement of the plunger is not limited to the speed or duration of a cam lobe. Higher injection pressures .
High pressures are available throughout the entire engine operating range.
An intensifier piston in the injector multiplies hydraulic force on the plunger. The injector uses high pressure engine oil to activate the piston. Thus the term hydraulically activated. The Injection pressure of the fuel can be controlled in a range from 3,000 to 21,000 psi. The HEUI is hydraulically actuated by high pressure engine oil supplied by a gear driven high pressure oil pump.