According to the Cup game on the official site, it's Hal.
it's also mentioned in this online review: http://blog.bookeazy.com/2008/08/30/movie-reviewwall%C2%B7e/
Chat with our AI personalities
Walter
the main character's name is wall e
Orion
The vacuum's name is VAQ-M.
WALL-E : Waste Allocation Load Lifter - Earth Class .