TM 5-2410-241-23-1
0005
AIR INLET AND EXHAUST SYSTEM
0005
The components of the air inlet and exhaust system control the quality of air and the amount of air that is available
for combustion. The components of the air inlet and exhaust system are:
Air cleaner
Turbocharger
Aftercooler
Cylinder head
Valves and valve system components
Piston and cylinder
Exhaust manifold
Inlet air is pulled through the air cleaner into the air inlet (Figure 1, Item 2) by the turbocharger compressor wheel
(Figure 1, Item 3). The air is compressed and heated to about 300F (150C) before the air is forced to the
aftercooler (Figure 1, Item 1). As the air flows through the aftercooler the temperature of the compressed air lowers
to about 180F (82C). Cooling of the inlet air increases combustion efficiency. Increased combustion efficiency
helps achieve the following benefits:
Lower fuel consumption
Increased horsepower output
The aftercooler (Figure 1, Item 1) is a water jacket aftercooler. This cools the turbocharged inlet air with the engine
coolant.
From the aftercooler, air is forced into the inlet manifold (Figure 1, Item 7). Air flow from the inlet chambers into the
cylinders is controlled by inlet valves (Figure 1, Item 9). There are two inlet valves and two exhaust valves
(Figure 1, Item 8) for each cylinder. The inlet valves open when the piston moves down on the intake stroke. When
the inlet valves open, cooled compressed air from the inlet port is pulled into the cylinder. The inlet valves close
and the piston begins to move up on the compression stroke. The air in the cylinder is compressed. When the
piston is near the top of the compression stroke, fuel is injected into the cylinder. The fuel mixes with the air and
combustion starts. During the power stroke, the combustion force pushes the piston downward. The exhaust
valves open and the exhaust gases are pushed through the exhaust port into the exhaust manifold (Figure 1,
Item 6) as the piston rises on the exhaust stroke. After the exhaust stroke, the exhaust valves close and the cycle
starts again. The complete cycle consists of four strokes:
Inlet
Compression
Power
Exhaust
Exhaust gases from exhaust manifold (Figure 1, Item 6) enter the turbine side of the turbocharger in order to turn
turbocharger turbine wheel (Figure 1, Item 4). The turbine wheel is connected to the shaft that drives the
compressor wheel. Exhaust gases from the turbocharger pass through exhaust outlet (Figure 1, Item 5), a muffler
and an exhaust stack.
0005-2
