TM 9-2350-277-20-1
THEORY OF OPERATION
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SCOPE
This section describes how major systems and components of the carrier operate. An understanding of how each part
functions in a system and how components relate to each other will help solve possible maintenance problems with the carrier.
POWER PLANT
The power plant consists of the diesel engine and transmission. The fuel, exhaust, cooling, starter, generator, and engine air
systems are support systems for the power plant.
DIESEL ENGINE
The diesel engine is the primary source of power for the carrier. The engine converts air and diesel fuel into energy and
delivers this power to the transmission.
STARTER
The engine is equipped with a heavy duty starter. The starter, with built-in solenoid, is used to crank the engine for starting.
GENERATOR
The generator is part of the carrier electrical system. It is driven directly by engine power. The generator charges the batteries
in the carrier when the engine is running. A regulator mounted in the driver’s compartment keeps the voltage at correct levels.
OIL SYSTEM
Oil system provides lubrication for the engine. Oil is cycled throughout the engine by a pump. The pump is located under the
front of the engine. An oil filter cleans the oil, and an oil cooler reduces oil temperature.
FUEL SYSTEM
Diesel fuel is stored in two fuel tanks located at the rear of the carrier. Fuel is drawn from fuel tanks by the fuel pump which
pumps fuel through filters to the engine injectors. The injectors force fuel into combustion cylinders where it is mixed with air
and changed into energy.
TRANSMISSION
The carrier uses hydromechanical transmission with hydrostatic steering. The transmission has its own oil system with filters
and separately mounted oil cooler. This transmission oil system is separate from the engine oil system.
The transmission delivers power from the engine to the left and right final drives. The left and right final drives are driven by
propeller shafts. The final drives deliver power to drive sprockets in the suspension system.
EXHAUST SYSTEM
Major exhaust system parts are the turbocharger, exhaust manifolds, muffler, and exhaust pipes.
The turbocharger is driven by exhaust gases from the engine. The turbocharger helps the engine develop more power and
operate more efficiently. The exhaust manifolds carry the exhaust gases to the turbocharger from the engine. The muffler cuts
down engine noise and allows exhaust to escape through the exhaust pipes to outside of the carrier.
COOLING SYSTEM
The cooling system cools the engine and transmission. It consists of a fan, fan drive, fan speed control assembly, radiator,
coolant pump, auxiliary tank, transmission oil cooler, engine oil cooler, and thermostats. The cooling system contains
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