Honeywell's Adriane Brown On Turbocharging

Auto makers are working quickly to develop more efficient engines as consumers, particularly in the U.S., demand better fuel economy. One technology that is seeing a resurgence is turbocharging. Turbos have typically been used to create more powerful engines, but they can also help in making engines more efficient. They are also used in most diesels, which are usually get better mileage than similar-sized gasoline engines? [b]Wall Street Journal[/b]: Explain turbocharging in a few sentences.