For ur kind information sir, EFI is a system, composed of many integral parts.
The old mechanical devices used to mix petrol with air and regulate its flow, were carburettors. Now this function is performed by EFI system, which not only enhances the fuel economy, but also the performance of the engines in terms of power output also. I dont know ur source of information, but if u really want to know about it, i can only refer a link to u mere bhai.

http://auto.howstuffworks.com/fuel-injection1.htm

Visit the link its useful in other aspects also.

Btw, u can call the EFI as an electronic carburetor.

Take care...

Allah Hafiz !!!