http://gm-volt.com/2008/07/26/gm-explains-why-the-14-l-ice-range-extender-was-chosen-for-the-volt/
excerpt:
On Friday GM dedicated a new advanced powertrain engineering center in Pontiac Michigan. The 450,000 square foot, $450 Million facility will use new specialized technology and procedures to more rapidly roll out advanced fuel efficient powertrains. It should be able to cut 10 weeks off of the typical powertrain development cycle. The Volt’s hardware will take center stage at the facility and per GM, "the Volt’s electric drive unit, motors, power electronics and engine will be tested in this center."
The range extender has been chosen. (ICE) Very interesting discussion on pros and cons follows. Moving right along.
I'm one of those grid-only boosters who will buy his Volt, if possible, without the ICE.