Fueling the combustion engine was still up for debate. Ford advocated ethanol made from corn, in part because he and other auto executives thought there wasn't enough petroleum in the world on which to base a long-term business. Then around 1930, a series of huge oil strikes in East Texas made that argument temporarily obsolete. The gasoline-powered internal combustion engine has reigned supreme ever since.

Now, however, some of the leading engineers in the industry are rethinking this dynamic duo. New concerns about the security of Mideast oil reserves, renewed fears that oil reserves will soon begin to decline, and ever more pressing worries about global warming are helping to power research into alternative combinations. The ultimate goal is to reduce the overall use of hydrocarbons by the average car, if only to ensure that the auto- mobile itself can continue to be the transport product of choice as tens of millions of new consumers in countries like China and India come to market in the decades ahead.

Automakers, says David Hermance, one of Toyota's top environmental engineers, "have to reduce the resource footprint of their products, or they will put themselves out of business."

Hybrid and Mighty
A good place to drill into the latest thinking on alternative cars is through the Electric Vehicle Association of the Americas. At a recent meeting of the EVAA in Sacramento, California - the automotive industry's least favorite state capital - engineers, academics, marketers, and corporate managers gathered to discuss their visions of the future of the automobile.