The device that uses exhaust gases to force extra compressed air into an engine is a turbocharger. It is a forced-induction system that uses otherwise wasted exhaust energy to increase the amount of air entering the cylinders.
A turbocharger contains two main rotating sections connected by a shaft. Exhaust gases spin a turbine on the engine’s hot side; that turbine drives a compressor on the intake side. The compressor pressurizes incoming air, allowing the engine to burn more fuel and produce more power from a given displacement. An intercooler may then cool the compressed air before it enters the engine, while a wastegate helps control boost pressure.
The turbocharger is often confused with a supercharger. Both compress intake air, but a conventional supercharger is mechanically driven by the engine, usually through a belt connected to the crankshaft. A turbocharger is driven primarily by exhaust-gas energy, although electrically assisted designs also exist.
Swiss engineer Alfred Büchi’s 1905 patent is commonly regarded as a foundational turbocharger design. Turbocharging first became important in aircraft and diesel applications before appearing in production passenger cars, including the Chevrolet Corvair Monza and Oldsmobile Jetfire in 1962.