SECTION III: PRINCIPLES OF OPERATION
TM 9-2350-256-20
Fuel from the fuel pump assembly (7) is filtered through the fuel/water separator fuel filter (9) and passes into the fuel
injector pump (23). This pump is located in the engine V between the cooling fans. The fuel injector pump delivers
accurately metered quantities of fuel under high pressure to each cylinder. An integral governor, of the mechanical
centrifugal type, is used to control fuel delivery as a function of engine speed. Engine shutoff is accomplished by a
normally open solenoid control unit in the fuel injector pump. The engine fuel shutoff switch on the master control panel
actuates the circuit to close the solenoid. Closing of the solenoid cuts off fuel delivery from the injector pump and stops
the engine. The engine is equipped with a manual fuel shutoff control to stop the engine if the electric fuel shutoff should
fail. A bleeder pressure-relief valve in the pump outlet maintains a constant fuel pressure by allowing any accumulated
air and excess fuel to return to the fuel tanks through the engine and fuel tank fuel return lines, check valve, hose, and
selector valve. Excess fuel is used to lubricate and cool the fuel injector pump. The check valve prevents a backflow of
fuel into the injector from the fuel return line and prevents continued engine operation after the fuel shutoff valve is
closed.
Twelve stainless steel fuel lines (13) carry fuel under high pressure from the fuel injector pump (23) to the 12 fuel injector
nozzles (15) on the left and right banks of the engine. The nozzles inject a fine spray of metered fuel under pressure into
each cylinder. Excess fuel is carried from the nozzles through fuel return hose assemblies (2) on each cylinder bank to
the fuel return system.
A hand-operated purge pump, next to the driver's seat, provides a means of purging the fuel injector pump (23), fuel
filters (3 and 9), and engine fuel lines of air. The air is forced by the fuel pressure from the purge pump through the
engine fuel lines and back to the fuel tanks through the injector pump fuel return line.
b.
AIR INTAKE SYSTEM
Two dry-type air cleaners, mounted in the right and left rear of the crew compartment, filter intake air for the engine. A
damper control, mounted on each air cleaner, is used to select air intake from either the crew compartment or from
outside the vehicle.
c.
EXHAUST SYSTEM
Exhaust pipes connect each exhaust manifold to a turbosupercharger. Exhaust gases are ejected from the engine, via
exhaust pipes, through deflector-type louvers at the rear of the vehicle.
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