What device uses exhaust gases to force more air into an engine?

A turbocharger uses exhaust gases to force more air into an engine.

A turbocharger is a forced-induction device with two linked turbines on a common shaft. Exhaust gases spin the turbine on the exhaust side, which drives a compressor on the intake side. The compressor packs more air into the cylinders, allowing the engine to burn more fuel and produce more power from a given displacement.

Turbocharging recycles energy that would otherwise leave through the exhaust. Many turbocharged engines use an intercooler to cool the compressed intake air before it enters the cylinders; cooler air is denser, so more oxygen can fit into the combustion chamber.

The main mix-up is with a supercharger. Both devices force extra air into an engine, but a supercharger is usually driven mechanically by the crankshaft, often with a belt. A carburetor meters fuel, while an intercooler reduces intake-air temperature; neither is the exhaust-powered air compressor described in the question.