How does the Audi A2's FSI fuel system work?

I've heard that the Audi A2 has a special FSI fuel system. Can you explain how it works and what its benefits are?

The Audi A2's FSI fuel system uses direct injection to deliver fuel and air directly into the combustion chamber, resulting in better fuel efficiency and lower emissions.

Not only does the FSI fuel system in the Audi A2 improve performance and emissions, it also allows the engine to run more smoothly and quietly.