Fuel System Operation and Tests
There are two sources of excess fuel incorporated into
The supply pump pressurizes the fuel so that it flows
the system. The supply pump supplies more fuel to the
through the filter to the injection pump galley. Supply
pump than is required by the engine, and the nozzle
pump output pressure will vary depending on load and
requires excess fuel to lubricate the nozzle valve. A
leak-off line (L) returns this excess fuel to the tank
from both the pump and nozzles.
The galley is kept full by the supply pump. Injection
pump plungers further pressurize the fuel. Injection
pressure lines route the fuel to the nozzles (C).
The high pressure fuel (K) opens the nozzle valve and
forces fuel out the small orifices in the nozzle tip. This
atomizes the fuel as it enters the combustion chamber.