MOTOR AS-GOVERNOR 1190645 - Caterpillar

Illustration 1 g01120694
Air inlet and exhaust system (1) Inlet valves (2) Exhaust valves (3) Exhaust manifold (4) Inlet manifold (5) Muffler (6) Air cleaner (7) Compressor side of turbocharger (8) Turbine side of turbochargerThe components of the air inlet and exhaust system control the quality of air and the amount of air that is available for combustion. The air inlet and exhaust system consists of the following components:
Air cleaner
Turbocharger
Cylinder head
Valves and valve system components
Piston and cylinder
Inlet manifold
Exhaust manifoldNote: The following description of the operation of the air inlet and exhaust system assumes that the engine is developing boost pressure. Inlet air passes through air cleaner (6) into the air inlet of the turbocharger compressor (7). A turbocharger is used in order to increase the flow of air into the engine. This increase in air flow pressurizes the combustion air supply for the engine. The pressure that is placed on the inlet air allows a larger volume of air to be compressed into the cylinder. This compressing of the inlet air is referred to as engine boost. The compressing of air causes the air temperature to rise to about 204 °C (400 °F). Compressing the inlet air increases the combustion efficiency of the engine. This also increases the engine's horsepower output.From the turbocharger, air enters inlet manifold (4). Air flow from the inlet manifold to the cylinders is controlled by inlet valves (1). There are two inlet valves and two exhaust valves (2) for each cylinder. The inlet valves open at the top center position of the piston. When the inlet valves open, compressed air enters the cylinder through the inlet ports. The inlet valves close as the piston reaches the bottom center position. This is called the inlet stroke of the engine. As the piston begins to travel back to the top center position on the compression stroke, the air in the cylinder is compressed to a very high temperature. When the piston is near the end of the compression stroke, fuel is injected into the cylinder and mixes with the compressed air. This causes combustion to start in the cylinder. Once combustion starts, the combustion force pushes the piston toward the bottom center position. This is called the power stroke. The exhaust valves open when the piston moves toward the bottom center position and the exhaust gases are pushed through the exhaust port into exhaust manifold (3) as the piston travels toward top center on the exhaust stroke. The exhaust valves close and the cycle starts again. The complete cycle consists of four strokes:
Inlet
Compression
Power
ExhaustThe exhaust gases from the cylinder are forced into exhaust manifold (3). The flow of exhaust gases from the exhaust manifold enter the turbine side of the turbocharger (8). The flow of the exhaust gas and the heat of the exhaust gas causes the turbine wheel in the turbocharger to spin. The turbine wheel is connected to a shaft that drives the compressor wheel. Exhaust gases from the turbine wheel exit the turbocharger and flow