hi to all, I can make you the example of the injectors mounted on a scania engines that have passed recently by the pde system (injectors, pump) to the system xpi (commonrail)
in the case of the pde, the control unit sends a constant current and constant energizing the coil when the injector must not inject, and when the controller removes power from the coil loses its magnetism by opening a valve that does fill the chamber of the pump, and then varying the time of the excitement of the coil and the ecu adjusts how much fuel is injected.
the xpi system works in the reverse as regards the electrical part, when the coil ? energized attracts a s? a plate, which through a sphere, opens a passage of diesel fuel (return) that does relieve the pressure in the upper part of the pin, and for a matter of difference of pressure between the top and lower the needle rises and injects the diesel, thanks to this system not linked to the camshaft as the pde we can have both the pre and post injections even as short as it all depends on the time that the control unit sends and removes power to the coils
Quote
