Supercharging your car...

Supercharging your car makes more power by forcing more air into your engine just like an Exhaust driven Turbocharger does.
This allows you to burn more fuel.
The difference is that the compressor is driven directly by the engine rather than the exhaust gasses. The one shown is a VW VR6 Motor with an aftermarket low boost "supercharger" fitted.
In this case it is actually a centrifugal compressor just like a Turbocharger uses, but driven by an auxiliary drive belt