F 350 4WD Super Duty V8-6.4L DSL Turbo (2008)
Main Injection Step 2
^ When the piezo actuator (1) is commanded on the actuator is energized (which causes the piezo discs to deform and create a downward force) and
pushes the valve piston (8) downward.
^ The downward force of the valve piston pushes the valve mushroom (4) and spring down which opens up a bore hole that connects the high pressure
fuel to the fuel return line (6).
^ When this happens it allows a small amount of high pressure fuel to enter the fuel return line (6) effectively dropping the pressure in the control piston
chamber (2).
^ This pressure drop is enough for the force (F2x) on the nozzle needle (5) in the high pressure chamber to overcome the force (F1x) in the control
piston chamber (2).
^ This allows the nozzle needle (5) to move upward uncovering the six spray holes and allowing high pressure fuel to atomize and enter the combustion
chamber.
