How does the Audi A2's fuel efficient engine work?

I've heard that the Audi A2 has a highly efficient engine, but how does it actually work and what makes it stand out from other cars in terms of fuel economy?

The Audi A2's engine utilizes direct injection technology, which allows for a more precise fuel delivery and therefore better fuel efficiency. In addition, the engine's lightweight design and aerodynamic features also contribute to its impressive fuel economy.