High Pressure Fuel Supply

Fuel comes from an inside chamber of the pump through a feed bore and metering slit in the distributor piston into a high pressure chamber of the pump located above the distributor piston.

When the cam rotates, the distributor piston is given a turning/lifting motion because of the cam rolling on the rollers of the roller ring. This rotary motion opens and closes the metering slits and control bores in the distributor piston and head. Pressure is produced by the lifting motion of the distributor piston after closing the feed bore. Fuel is delivered and distributed to the different outlets by way of a distributor groove. The produced high pressure lifts the pressure valve off of its seat and fuel is pressure-fed by an injection line to the fuel injector. Fuel delivery is stopped when the control bore of the distributor piston reaches the control edge of the control valve. From this moment on the high pressure chamber is connected by an internal bore with the pump's inside chamber. The excessive fuel is returned to the pump's inside chamber during the remaining lift action (piston's remaining stroke). See Figure.