No, DSi is an incremental upgrade.
Generations have so far always been defined by when a console is built from scratch is released - not a hardware revision (even a major hardware revision such as the DSi) is released. Just like the GBC was still a gameboy the DSi is still a DS.
@BladeOfGod. You are just plain wrong. Look through the wikipedia articles on the generations of video-gaming to get an idea of how the system actually works.








