and finely atomized fuel into the cylinder at the correct
transfer fuel from the service tank to the fuel injectors.
The pump circulates an excess fuel supply through the
time. Unit injectors combine the high pressure pump
injectors. The excess fuel purges air from the system and
necessary for proper injection and the injection nozzle
cools the injectors. The used fuel is returned to the
in one unit. The injectors create the high fuel pressure
engine fuel inlet through the cooler.
required for efficient injection. They both meter and
inject the correct amount of fuel required by the engine
The fuel pump is mounted on an adapter attached to
load, and atomize the fuel for mixing with the air in the
the flywheel housing and is driven off the end of the
blower drive gear by a coupling fork. The fuel pump is
a right-hand rotation pump. The fuel pump pressure is
The injector fits snugly in the injector tube
regulated by a spring-loaded relief valve that is
installed in the cylinder head. The tip projects slightly
incorporated into the pump casing. The relief valve is
below the bottom of the cylinder head. Jacket water
set to lift at 100 psig in the event of high pump discharge
circulates around the lower part of the injector tube to
pressure. The excess fuel recirculates from the pump
keep it cool.
discharge to the suction side of the pump.
Each injector has two connections, one to supply
FILTER ASSEMBLY. The fuel filter assembly
fuel and the other to carry away bypassed fuel (spill).
consists of four housing units in a duplex arrangement.
The injector is actuated by the injector rocker, which
A selector handle is used to shift from the active
works directly off the camshaft. The amount of fuel
elements to the standby units. Each filter unit consists
injected is regulated by the control rack which is
of a shell, a cover, and five replaceable filtering
operated by a lever secured to the rack control tube. The
elements. The filter elements slide over a filter guide.
control tube is positioned by linkages from the governor
The fuel enters the shell and passes inward through the
filter element, where it enters the filter guide and passes
to the filter outlet. Check valves are installed in the filter
COOLER. The return fuel cooler is of the shell and
outlet connections to prevent fuel backflow to the
tube design. The cooler is a single-pass heat exchanger.
standby unit. The filter elements should be replaced
The heads are bolted to the shell assembly. Baffles are
when the differential pressure exceeds 15 psid.
used along the length of the tube bundle to support the
tubes and to direct the flow of fuel. Seawater is used as
FUEL BLOCK AND CHECK VALVE
SYSTEM. The fuel junction block distributes fuel
the coding medium.
from the filter to the fuel manifolds through flexible
Now that we have looked at the Detroit Diesel's fuel
lines. A valve, located in the inlet piping before the fuel
system, let's examine its lubricating oil system.
junction block, prevents fuel stoppage through the
injector, which could cause cylinder head damage. A
Lubricating Oil System
check valve, installed in the fuel junction block on the
outlet (spill) side, prevents fuel from draining from a
This efficient lubricating oil system provides
high mounted fuel tank back into the injectors when the
lubrication for both the diesel engine and the generator
engine is not running. An orifice (0.136 inch and 0.1695
from a common system. The Detroit Diesel's lubricating
inch) drilled in the fuel pressure relief valve plug
oil system consists of the following main components:
maintains pressure in the fuel system.
FUEL MANIFOLDS. The fuel manifolds are
attached to the top of the cylinder block on each bank of
Oil pump and relief valves
the engine. Fuel connectors, installed in the bottom of
the manifold, supply fuel to the injector and return
excess fuel from the injector back to the return passage
in the manifold. The manifolds are installed with the
supply passages on the outboard side on each injector
bank. Surplus fuel is returned to the fuel strainer inlet
through the return fuel cooler.
Let's look briefly at each of these components. For an
in-depth view, again, we recommend you consult the
required for satisfactory engine operation depends on
the injection of a small quantity of accurately metered
appropriate technical manuals.