Charles,

Yes the Civc CVT for example uses belts and variable diameter pulleys (I had a 1941 motorcycle that also had a belt driven CVT).

If you want to understand the HSD there is a neat simulation of one (For the older Prius). I have a copy of it at:

http://doctord.dyndns.org:8000/cours...sSimulator.jar

You will need a working Java Interpreter to run it. Get a free one from Sun at:

http://java.sun.com/j2se/1.4.2/download.html

JeffD