General Motors' development of the Chevrolet Volt has been conducted with unprecedented publicity for the company. In fact, it has had so much publicity that it has led some skeptics to believe the program is a mere publicity stunt. Given that the American industry needs more good news for multiple reasons, this theory is alluring. Either way, we keep learning more about the GM program at almost every auto show and on many occasions in between.

At a "town hall" meeting with Volt enthusiasts in New York, the company spelled out many more details about its targets for the production car. Here's what we learned:

• It will definitely be a small, four-door hatchback based on GM's global small-car architecture, as the concept car is, and it will be built on an existing assembly line.
• The car will likely be low-slung and narrow, because aerodynamics will be important to achieving the targeted fuel economy. Seats will "fit like a tailored suit, not a bulky winter coat," says the Volt's Chief Engineer Andrew Farah.
• The car's lithium-ion battery pack will have 16 kilowatt/hours of capacity - the amount necessary to travel 40 miles on an electric charge.
• The car will have an "intelligent" on-board battery charger that can automatically charge from any type of typical household electric current - either 110-volt or 220-volt AC.
• The battery pack will consist of 250 individual cells, wired in series. If any one of them fails, the whole pack will be dead. The pack will be liquid-cooled.
• Those batteries will use one of two technologies: lithium-ion nano-phosphate batteries from A123 systems in Massachusetts, or lithium-ion magnesium batteries from LG Chem. Neither technology was used in the lithium batteries that exploded spontaneously in laptop computers. Although lithium battery technology is advancing, GM has frozen this technology for the first-generation Volt to meet its November 2010 production target.
• GM is targeting an acceleration time from 0 to 60 mph of between 7 and 9 seconds, similar to the range of most family sedans today.
• The Volt will initially be sold only in certain states or cities, but will roll out nationwide "within months" after that.

A few guests at the meeting last night asked what will take the company so long to develop batteries for the Volt.

In addition to developing software to tell the engine when to start in any of thousands of different situations and how fast to run it, figuring out how to deal with stale gas and oil if users don't drive far enough to start the engine, and testing full-size battery packs, GM expects it will take time to develop public knowledge of how to operate the Volt.

For example, teaching consumers how often they should expect to recharge the car and to fill it with gas, and working with power companies to ensure that Volt buyers get discounted off-peak electric rates for charging at night. Currently, there is no EPA protocol for measuring the fuel economy of a plug-in hybrid.

Bob Lutz, General Motors vice president of global product development, says he is 94 percent positive GM will meet its target deadline of November 2010 to introduce the Volt. Then again, Bob is known for bluster. One thing is more and more certain: If the Volt turns into a mere publicity stunt, it will likely be the most elaborate and expensive one in history.

—Eric Evarts

See the 2008 New York auto show coverage.