PUMP AS-FUEL 3608918 - Caterpillar

Illustration 1 g01356032
Air inlet and exhaust system
(1) Exhaust manifold
(2) Injector
(3) Glow plug
(4) Intake manifold
(5) Aftercooler core (if equipped)
(6) Exhaust outlet
(7) Turbine side of turbocharger
(8) Compressor side of turbocharger
(9) Air intake from the air cleaner
(10) Inlet valve
(11) Engine cylinder
(12) Exhaust valve 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 air inlet and exhaust system consists of the following components:
Air cleaner
Turbocharger
Aftercooler (if equipped)
intake manifold
Cylinder head, injectors and glow plugs
Valves and valve system components
Piston and cylinder
Exhaust manifoldEngines which are naturally aspirated pull outside air through an air cleaner directly into the intake manifold (4). The air flows from the intake manifold to the engine cylinders (11). The air mixes with the fuel and leads to combustion. After combustion, the exhaust gases flow directly to the outside air through the exhaust manifold (1).A turbocharger increases the temperature and the density of the air that is sent to the engine cylinder. This condition causes a lower temperature of ignition to develop earlier in the compression stroke. The compression stroke is also timed in a more accurate way with the fuel injection. Surplus air lowers the temperature of combustion. This surplus air also provides internal cooling.In turbocharged engines, air is drawn in through the air cleaner into the air intake of the turbocharger (9) by the turbocharger compressor wheel (8). The air is compressed and heated to about 150 °C (300 °F) before the air is forced to the aftercooler (5). As the air flows through the aftercooler the temperature of the compressed air lowers to about 50 °C (120 °F). Cooling of the intake air increases combustion efficiency. Increased combustion efficiency helps achieve the following benefits:
Lower fuel consumption
Increased horsepower output
Increased engine torque
Increased durability of the engine
Reduced particulate emissionFrom the aftercooler, air is forced into the intake manifold (4). Air flow from the intake manifold to the cylinders is controlled by inlet valves (10). There is one inlet valve and one exhaust valve 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 intake port is forced into the cylinder. The complete cycle consists of four strokes:
induction
Compression
Power
ExhaustOn the compression stroke, the piston moves back up the cylinder and the inlet valve (10) closes. The cool compressed air is compressed further. This additional compression generates more heat. Note: If the cold starting system is operating, the glow plugs (3) will also heat the air in the cylinder.Just before the piston reaches the Top Center (TC) position, fuel is injected into the cylinder. The air/fuel mixture ignites. The ignition of the gases initiates the power stroke. Both the inlet and the exhaust valves are closed and the expanding gases force the piston downward toward the Bottom Center (BC) position .From the BC position, the piston moves upward. This initiates the exhaust stroke. The exhaust valve (12) opens. The exhaust gases are forced through the