How does a Simulation Engine work ?

I am just curious to know how does simulation engine work behind the scene ? does some body have literature related to this area ?

what is the architecture of a simulation engine ?
i am definitely not going to try to build one. just curious.

There's an excellent book titled "Simulation Modeling & Analysis" 4th Edition 2007 by Averill M. Law that explains everything you would ever want to know (and some things you don't want to know) about simulation including a detailed look behind the scenes at a simulation engine. This book is often referred to as "the bible" of simulation.

I have the book. It is really a good one for discrete event simulation modeling.

You could also Google "discrete event simulation". A lot of good introductory materials can be found. Just list a few:

http://en.wikipedia.org/wiki/Discrete_event_simulation
http://www.cs.wm.edu/~esmirni/Teachi...DESAFC-1.1.ppt