TM 9-2350-277-34
THEORY OF OPERATION
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SCOPE
This section describes the functions of the hull system. Also it describes the power plant, auxiliary automotive system,
suspension and electrical systems, and special equipment.
POWER PLANT
The diesel engine and transmission are major parts of the power plant. The dc generator, exhaust, cooling, 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 changes air and diesel fuel into energy and
delivers this power to the transmission. The diesel engine consists of three major systems: fuel, oil, and starting.
In the fuel system, diesel oil is stored in the fuel tanks. The fuel is drawn through one filter and pumped through the other
filter to the engine. The injectors force fuel into combustion cylinders where it is mixed with air and changed into energy.
The oil system provides lubrication for the engine. Oil is cycled throughout the engine by a pump. The pump is located at the
lower front of the engine. An oil filter cleans the oil, and an oil cooler reduces oil temperature.
The engine is equipped with a heavy duty starter. The starter, with built in solenoid, is used to crank the engine for starting.
TRANSMISSION
The carrier uses a 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.
DC GENERATOR
The dc 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 near the driver keeps the voltages at the correct level.
EXHAUST SYSTEM
Major exhaust system parts are the turbocharger, exhaust manifolds, and muffler.
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 outside 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
approximately 53 quarts of liquid coolant. The liquid coolant is cycled through the engine and transmission oil cooler by the
coolant pump. This process keeps the engine and transmission temperature in a safe operation range.
As coolant flows through the engine, it absorbs heat from the engine and transmission oil coolers. The heated coolant then
flows to the radiator to remove coolant heat. The coolant fan pulls outside air in and through the radiator to remove heat. The
fan is powered by the engine through a fan drive.
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