TM 5-4320-306-10
1-15. PUMP DRIVE OPERATION
The impeller rotates at engine speed. Adjusting engine speed changes the impeller speed, and results in changes to the
suction and discharge pressures. Increasing or decreasing engine speed increases or decreases the speed of impeller
rotation. By increasing or decreasing the speed of impeller rotation, the pumping rate and discharge head are increased
or decreased.
1-16. ENGINE
Engine subsystems are: electrical system, lubrication system, cooling system, and fuel system. The components and
functions of these subsystems are explained below.
a. Electrical system. The components of the engine electrical system are the batteries, starting motor, alternator,
and wiring harness. The batteries provide electric power to run the starting motor and start the engine. The alternator
recharges the batteries after the engine is started and provides power to all the electrical components through the wiring
harness.
b. Lubrication system. The components of the engine lubrication system are the lube oil pump, lube oil cooler,
and lube oil filter. The lube oil pump pumps oil to reduce friction between moving parts. The lube oil cooler reduces the
temperature of the lube oil which cools the engine. The lube oil filter removes impurities from the oil.
c. Cooling system. The major components of the engine cooling system are the cooling air blower, the cooling air
ducting, and the lube oil cooler. The primary coolant is the engine lube oil. The secondary coolant is forced air. The
lube oil circulating through the engine removes heat from the engine. The cooling air blower forces air onto the cylinders
and through the oil cooler. The forced air removes heat from the lube oil. The cooled lube oil again circulates through
the engine to remove heat.
d. Fuel system. The major components of the engine fuel system are the fuel feed pump, fuel injection pump,
fuel tank, fuel filter, and fuel lines. The fuel feed pump draws fuel from the fuel tank, through the filter, to the fuel
injection pump. The injection pump injects fuel into the engine cylinders. The fuel lines connect these components.
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