Fuel Divider
Simple but very precise. Fuel pressure works against a diaphram with a backing spring. At low flow fuel flows, the incoming fuel is forced through a divider (four tapered perimeter orifices on the perimeter of a plunger on above mentioned diaphram) to very precisely divide fuel to the individual nozzles. At higher pressures and flows, it is a wide open, simple manifold.
The purpose of the device is to compensate for uneven injector heights (I.E. favoring of low) and losses in spider lines at low flows.