So what is a turbocharger? A turbocharger, (or turbo), is a turbine-driven forced induction device that increases an internal combustion engine’s efficiency and power output by forcing extra air into the combustion chamber.
This improvement over a naturally aspirated engine’s power output is due to the fact that the compressor can force more air—and proportionately more fuel—into the combustion chamber than atmospheric pressure alone.
In naturally aspirated piston engines, intake gases are “pushed” into the engine by atmospheric pressure filling the volumetric void caused by the downward stroke of the piston (which creates a low-pressure area), similar to how liquid is drawn up into a syringe.
The objective of a turbocharger is to improve an engine’s efficiency by increasing the density of the intake gas (usually air), thereby allowing more power per engine cycle.
The turbocharger’s compressor draws in ambient air and compresses it before it enters into the intake manifold at increased pressure. This results in a greater mass of air entering the cylinders on each intake stroke. The power needed to spin the centrifugal compressor is derived from the kinetic energy of the engine’s exhaust gases.
A turbocharger may also be used to increase fuel efficiency without increasing power. This is achieved by recovering waste energy in the exhaust and feeding it back into the engine intake. By using this otherwise wasted energy to increase the mass of air, it becomes easier to ensure that all fuel is burned before being vented at the start of the exhaust stage.
ARTICLES SOURCES : https://www.melett.com/technical/what-are-turbochargers/