Turbocharge

"From backyard tuners to luxury limousine manufacturers, they've all relied on Buchi's turbocharger." Don Sherman, Automobile magzine 

Buchi reclaims lost energy to make engines more efficient (1905)

The turbocharger is similar to the supercharger but, instead of mechanically forcing extra air into the engine, it uses the exhaust to drive a turbine that boosts air in. Swiss engineer  Alfred Buchi (1879-1959) realized that using a turbine to make use of engine exhaust would actually recover otherwise lost energy to make the combustion cycle much more efficient. 

Turbochargers and diesel engines fit together perfectly since diesel engines have no throttle to stall the air flow to the turbine. They were first implemented commercially in two German passenger ships, in which the addition of the turbocharger increased the horsepower from 1750 to 2500. 

The purpose of a turbocharger is to increase the mass of
 air entering an engine to create more power

Putting Turbochargers into cars, however, proved a little harder. As it is the hot air from the combustion that drives the turbine, the materials that make it must be able to withstand high temperatures upto 1832°F (1000°C). This has been the issue that held back turbochargers from the mass market, but recently manufactures have been taking technology straight from space rockets to try and improve the material design. As rockets need to withstand much higher temperatures than 1832°F(1000°C), the hope is that their designs can be scaled down enough to make this a viable option for cars.

The most talked about car designs for the future, such as hybrids and fuel cell based vehicles, would benefit from the incorporation of a turbocharger into the plan. With their green design which can save a third of engine energy that would normally be wasted, it looks as if the turbocharger is here to stay.