GEAR (19 and 21 Teeth) 8S2132 - Caterpillar

Illustration 1 g01180656
Turbocharger in series
(1) Exhaust valve
(2) Inlet valve
(3) Air-To-Air Aftercooler
(4) Precooler
(5) High-pressure turbocharger
(6) Turbine inlet
(7) Wastegate
(8) Compressor outlet
(9) Turbine outlet
(10) Compressor inlet
(11) Turbine inlet
(12) Hose for the wastegate
(13) Turbine outlet
(14) Compressor outlet
(15) Low-pressure turbocharger
(16) Compressor inlet Basic Operation
The following components make up the air inlet and exhaust system:
Low-pressure turbocharger
High-pressure turbocharger
Precooler
Aftercooler
Cylinder head
Valves and valve train components
Piston and cylinder
Exhaust manifoldThe engines are equipped with two turbochargers in series. Turbocharged engines are more responsive and turbocharged engines have increased horsepower. Air is drawn through the air cleaner and flows to the compressor side of the low-pressure turbocharger. The low-pressure turbocharger compresses the air in order to create boost. The compressed air is sent to the air inlet of the high-pressure turbocharger. The high-pressure turbocharger compresses the air in order to create higher boost pressures. After the air exits from the high-pressure turbocharger the compressed air is cooled by the precooler.The precooler is a heat exchanger. The precooler uses coolant to extract the heat from the compressed air. The air then flows through the Air-to-Air Aftercooler (ATAAC). The air will then enter the cylinder head. The water supply for the precooler is regulated. The water supply is shut off below 1200 RPM. Cooling the compressed air increases combustion efficiency. The inlet valves control the air flow into the combustion chamber. Each cylinder contains two inlet valves and two exhaust valves. The inlet valves open when the piston moves down on the inlet stroke. When the inlet valves open, cooled compressed air 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 occurs. 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 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:
Intake
Compression
Power
ExhaustTurbocharger
Illustration 2 g01114531
(1) Compressor housing
(2) Oil inlet port
(3) Bearing
(4) Turbine housing
(5) Turbine wheel
(6) Air inlet
(7) Exhaust outlet
(8) Compressor wheel
(9) Bearing
(10) Oil outlet port
(11) Exhaust inlet The two turbochargers work together in order to produce boost across the entire engine RPM range. The increased boost at low RPM fills the combustion chamber with dense air. The dense air mixes with the fuel in order to promote a complete combustion.The turbochargers have a compressor wheel (8) and a turbine wheel (5). The compressor wheel and the turbine wheel are connected to a common shaft. The shaft is supported by bearings (3 & 9). The bearings are lubricated by pressurized engine oil. The oil enters through oil inlet port (2). The engine oil lubricates the bearings and the oil removes heat. The oil returns to the oil pan through oil outlet port (10).The high-pressure turbocharger is