To answer the initial question...no, it is not a full-on ORM layer.
There is also DataMapper if you don't like Doctrine. I guess it may feel redundant because you are extending the functionality of CI because it doesn't use a true ORM by default.
Honestly if I were going to use CodeIgniter, I would just stick with using Active Record and CI's default functionality...if I wanted a framework with a true ORM, I would pick one that ships with one. That's just my opinion though.