This is a common misunderstanding. According to Kurzweil's timeline, AI surpassing human intelligence is only a stepping stone to the singularity, the former happening around 2029, the latter around 2045.
Rather, the singularity refers to the point at which the exponential slope representing technological progress begins to approach infinity. What this mathematical model means for reality is anybody's guess, and the majority of the predictions that have been made are pure conjecture.
To me, the name actually seems like a better fit for Vinge's or Good/Yudkowsky's predictions than Kurzweil's. They both have specific "singularity" points, while Kurzweil's "singularity" is just an ever-growing exponential (or super-exponential).