SWITCH AS-MAGNETIC 2888632 - Caterpillar

Illustration 1 g03320222
(1) Inlet air supply (2) Low-pressure turbochargers (3) High-pressure turbochargers (4) Aftercooler (5) Air return from aftercooler (6) Wastegate (7) Wastegate signal pressure line (8) Exhaust gas outlet
Illustration 2 g03320307
(1) Inlet air supply (2) Low-pressure turbocharger (3) High-pressure turbocharger (4) Supply to aftercooler (5) Return from aftercooler (8) Exhaust gas outlet (9) Air manifold
Illustration 3 g03320237
Rear view of engine (6) Wastegate (7) Wastegate signal pressure lineInlet air is pulled through the air filters into the air inlet (1) for each low-pressure turbocharger (2). The rotation of the low-pressure turbocharger compressor wheel forces the compressed air through air manifolds (9) and into the inlet for the high-pressure turbochargers (3) .The rotation of the compressor wheel in the high-pressure turbochargers further pressurizes the inlet air. Pressurizing the inlet air also increases the temperature of the inlet air. The compressed air exits the high-pressure turbochargers (3) and flows to the outlet to the aftercooler (4). The compressed air flows through the aftercoolers to the air intake manifolds (5). This cooled compressed air fills the inlet chambers in the cylinder heads. Air flow from the inlet chamber into the cylinder head is controlled by the intake valves. There are two intake valves and two exhaust valves for each cylinder. Refer to Systems Operation / Testing and Adjusting, "Valve Mechanism".The intake valves open when the piston moves down on the intake stroke. The cooled, compressed air is pulled into the cylinder from the inlet chamber. The intake valves close and the piston moves up on the compression stroke. 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 begins. The force that is generated by combustion pushes the piston downward on the power stroke.When the piston begins to move upward again, the piston is on the exhaust stroke. The exhaust valves open and the exhaust gases are pushed through the exhaust port into the exhaust manifold. After the exhaust stroke is complete, the exhaust valves close and the cycle begins again.Exhaust gases from the exhaust manifolds flow toward the rear of the engine and then up into the wastegate manifold. The wastegate manifold contains two possible flow paths for the exhaust gases. Under normal operating conditions, the exhaust gas continues through the wastegate manifold and into the turbine side of the high-pressure turbochargers (3). The hot exhaust gases cause the turbine wheel to rotate. The turbine wheel is directly connected to the shaft that drives the compressor wheel. The wastegate valve is also mounted to the wastegate manifold. The wastegate valve (6) utilizes a sensing line (7) that senses pressure in the inlet manifolds. If boost pressure increases above the setting on the wastegate valve (6), the valve opens and allows the exhaust gas to bypass the turbine wheel in the high-pressure turbochargers (3). When the exhaust gases bypass the turbine wheels, the turbine wheels slow down. When the turbine wheels slow down, the compressor wheels also slow down.