A turbocharger is a small radial fan pump driven by the energy of the exhaust gases of an engine. The purpose of a turbocharger is to compress the air flowing into the engine. It lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder.



To put it simply, a turbocharger comprises of a turbine and a compressor connected by a common shaft supported on a bearing system. The turbocharger is bolted to the exhaust manifold of the engine. It uses the exhaust flow from the engine to spin a turbine, which works like a gas turbine engine. The more exhaust that goes through the blades, the faster they spin.


On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. Compressor consists of two sections, the impeller or compressor wheel and the compressor housing. The compressor wheel is connected to the turbine by a forged steel shaft. As the compressor wheel spins, air is drawn in and is compressed as the blades spin at a high velocity. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.


The turbocharger bearing system is lubricated by oil from the engine. The oil is fed under pressure into the bearing housing, through to the journal bearings and thrust system. The oil also acts as a coolant taking away heat generated by the turbine.


Many turbochargers use a basic wastegate, which allows smaller turbochargers to reduce turbo lag. A wastegate regulates the exhaust gas flow that enters the exhaust-side driving turbine and therefore the air intake into the manifold and the degree of boosting. It can be controlled by a solenoid operated by the engine’s electronic control unit or a boost controller but most
production vehicles use a spring loaded diaphragm.