F548984 Force BLANKET, SILENCER - TOP (NOT SHOWN)

Illustration 1 g06471531Reference: For more information, refer to supplemental video "C9.3B Engine Air Inlet and Exhaust System" on Caterpillar Channel1.Note: Click or copy the following link into a web browser (a CWS login is required to access Caterpillar Channel1), or scan the following QR code using a QR enabled device.https://channel1.mediaspace.kaltura.com/media/1_qmhzbg63
Illustration 2 g06527995System Overview
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Air inlet and exhaust system
(1) Air-to-air aftercooler (ATAAC)
(2) Exhaust manifold
(3) Turbocharger
(4) Clean Emissions Module (CEM)
(5) Intake manifold
(6) Cylinder headThe engine has an electronic control system. The system controls the operation of the engine and Clean Emissions Module (CEM). The CEM consists of the following components: Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and electrical system components.Inlet air is pulled through the air cleaner . The inlet air is then compressed and heated by the compressor wheel of turbocharger to about 150 °C (300 °F). The inlet air is then pushed through air-to-air aftercooler core. As the air flows through the aftercooler, the temperature of the compressed air lowers to about 50° C (122° F). Cooling of the inlet air assists the combustion efficiency of the engine. Increased combustion efficiency helps to lower fuel consumption and increase power output.Aftercooler core is a separate cooler core. The aftercooler core is installed in front of the core of the engine radiator. Air that is ambient temperature is moved across the aftercooler core by the engine fan. The aftercooler core cools the turbocharged inlet air.From aftercooler core, the air is forced into the intake manifold. Air flow from the inlet manifold into the cylinders is controlled by the inlet valves.
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(7) Exhaust manifold
(8) Air inlet heater
(9) Aftercooler core
(10) Exhaust valve
(11) Inlet valve
(12) Air inlet
(13) Exhaust outlet
(14) Compressor side of turbocharger
(15) Turbine side of turbochargerThere are two inlet valves and two exhaust valves for each cylinder. Inlet valves open when the piston moves down on the inlet 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 will 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 valves open, and the exhaust gases are pushed through the exhaust port into the exhaust manifold. After the piston completes the exhaust stroke, the exhaust valves close and the cycle will start again. The complete cycle consists of four stages:
Inlet stroke
Compression stroke
Power stroke
Exhaust strokeExhaust gases from the exhaust manifold enter the turbine side of turbocharger to turn the turbine wheel. The turbine wheel is connected to a shaft which drives the compressor wheel. Exhaust gases from the turbocharger pass through the exhaust outlet pipe, the muffler, and the exhaust stack.Turbocharger
Illustration 5 g06237584
(1) Air intake
(2) Compressor housing
(3) Compressor wheel
(4) Bearing
(5) Oil inlet port
(6) Bearing
(7) Turbine housing
(8) Turbine wheel
(9) Exhaust outlet
(10) Oil outlet
(11) Exhaust inletThe turbocharger is installed on the center section of the exhaust manifold. All the exhaust gases from the engine go through the turbocharger. The compressor side of the turbocharger is connected to the aftercooler by a pipe.The exhaust gases enter turbine housing through the exhaust inlet (11). The exhaust gases then push the blades of turbine wheel (8). The turbine wheel is connected by a shaft to the compressor wheel (3). Clean air is pulled through the compressor housing air inlet (2) by rotation of the compressor wheel . The action of the compressor wheel blades causes a compression of the inlet air. This compressor allows the engine to burn more fuel. When the engine burns more fuel, the engine produces more power.When the load on the engine increases, more fuel is injected into the cylinders. The combustion of this additional fuel produces more exhaust gases. The additional exhaust gases cause the turbine and the compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, more air is forced into the cylinders. The increased flow of air gives the engine more power by allowing the engine to burn the additional fuel with greater efficiency.The operation of the wastegate is controlled by the boost pressure. At high boost pressures, the wastegate opens to decrease boost pressure. At low boost pressure, the wastegate closes to increase boost pressure. Closing the valve of the wastegate allows the turbocharger to operate at maximum performance. When the valve of the wastegate is opened, the rpm of the turbocharger is limited by bypassing a portion of the exhaust gases. The exhaust gases are routed through the wastegate which bypasses the turbine wheel of the turbocharger. Certain applications have turbochargers that are equipped with a smart wastegate. The smart wastegate performs the same function as a regular wastegate, but is also activated by a software-controlled electronic valve in addition to boost pressure. The smart wastegate keeps the wastegate closed during certain operating conditions to prevent wasting exhaust, regardless of boost pressure. The regular wastegate will activate whenever it senses a certain amount of boost pressure, regardless of engine operating conditions.Note: The turbocharger with a wastegate is preset at the factory and no adjustment can be made.Bearings (4) and (6) for the turbocharger use engine oil under pressure for lubrication and cooling. The oil comes in through oil inlet port (5). The oil then goes through passages in the center section to lubricate the bearings. This oil also cools the bearings. Oil from the turbocharger goes out through oil outlet port (10) in the bottom of the center section. The oil then goes back to the engine oil pan.Valve System Components
Illustration 6 g02396141
Valve system components
(40) Rocker arms
(41) Bridge
(42) Spring
(43) Pushrods
(44) Valves
(45) Lifter