Chevy's taking a moment to clear up some misconceptions about its eagerly anticipated plug-in hybrid, the Volt, which had long been assumed (by most) to use its gasoline-powered engine like a WWII submarine -- kicking on and charging the batts to full before switching off again. Alas, that's close but not completely accurate. The engine does serve only to feed the batteries (it's not connected to the wheels in any way) and will fire up when they are getting low. However, it will not fully recharge them, serving only to maintain a 30-percent charge as you keep on motoring. In other words, you'll need to plug that puppy in overnight if you want to to get back to silent running and successfully avoid detection by destroyer battlegroups on your morning commute -- or spy cameras.