KIT-ENGINE OVERHAUL 20R0645 - Caterpillar

Illustration 1 g00692826
Air Inlet And Exhaust System Schematic (1) Aftercooler (aftercooled engines) (2) Air inlet manifold (3) Exhaust manifold (4) Exhaust outlet (5) Turbocharger (6) Air inlet (7) Air cleanerThe components of the air inlet and exhaust system control the quality of the air that is available for combustion. These components also control the amount of the air that is available for combustion. The components of the air inlet and exhaust system are listed below:
Air cleaner
Turbocharger
Aftercooler (aftercooled engines)
Cylinder head
Valves and valve system components
Piston and cylinder
Exhaust manifold
Illustration 2 g00693191
Air Inlet And Exhaust System (1) Aftercooler (aftercooled engines) (3) Exhaust manifold (4) Exhaust outlet (6) Air inlet (8) Exhaust valve (9) Inlet valve (10) Compressor wheel (11) Turbine wheelInlet air is pulled through air cleaner (7). The inlet air is then compressed and heated by the compressor wheel of turbocharger (5) to about 150°C (300°F). The inlet air is then pushed through one of the following components: air-to-air aftercooled (ATAAC), jacket water aftercooled (JWAC) and air inlet cover. The inlet air is forced to air inlet manifold (2). The temperature of the inlet air at the air inlet manifold is about 43°C (110°F). Cooling of the inlet air increases the combustion efficiency. Increased combustion efficiency helps to lower fuel consumption. Also, increased combustion efficiency helps to increase horsepower output.The air to air aftercooled (ATAAC) system incorporates a separate air to air aftercooler core. This core is installed in front of the radiator of the engine or the core is installed beside the radiator of the engine. Air that is ambient temperature is moved across the aftercooler core by the engine fan and by the ram effect of the vehicle's forward motion. This cools the turbocharged inlet air.The jacket water aftercooled (JWAC) system uses engine coolant from the water pump in order to cool the hot turbocharged air. The JWAC system incorporates a water-to-air system that is mounted to the air inlet manifold.Inlet manifold (2) is a one-piece casting that also serves as a base for the valve cover. From the inlet manifold, the air is forced into the cylinder head in order to fill the inlet ports. Air flow from the inlet port into the cylinder is controlled by the inlet valves.There is one inlet valve (9) and one exhaust valve (8) for each cylinder. The inlet valve opens when the piston moves down on the inlet stroke. When the inlet valve opens, cooled compressed air from the inlet port is pulled into the cylinder. The inlet valve closes 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. After the power stroke is complete, the piston moves upward. This upward movement is the exhaust stroke. During the exhaust stroke, the exhaust valve opens, and the