Gasoline-Free Future

Detroit’s North American International Auto Show is always a showcase for wacky ideas and new design concepts. But this year, what really matters about the futuristic prototypes on display is what’s under the hood.

Faced with tough new fuel economy rules and increased pressure to reduce CO2 emissions, automakers are offering an array of alternative propulsion systems that could one day replace internal combustion engines.

There are hybrids, flex-fuels, diesels, plug-ins, and fuel cells on display, as well as enhanced gasoline engines, each offering its own argument for how to reduce dependence on oil and clean up the environment.

In Pictures: Cars Of The Future

The Cadillac Provoq is the latest example of General Motors' E-Flex propulsion system, first unveiled a year ago with its Chevrolet Volt plug-in hybrid concept. The Volt, now scheduled for production around 2010, has a small gasoline engine to recharge the battery while driving.

The Provoq has a different twist: It combines GM’s fifth-generation fuel cell system (half the size of its predecessor) with a lithium-ion battery to produce an electrically driven vehicle that uses no gas and emits only water. It can go 300 miles on a single tank of hydrogen (including 20 miles on electricity alone).

The Provoq has other cool features, too, including solar roof panels to power accessories (like interior lights or the audio system) and electronic (rather than mechanical) brakes. The front grille has louvers that close at highway speeds to enhance aerodynamics and open at low speeds to help cool the fuel cell. GM won't say when it might be produced, but is interested in producing a crossover with the same body style.

Honda also has a fuel cell car on display — the FCX Clarity — and this one is much closer to production. It is expected to get 68 miles per gallon and go 270 miles on a single tank of hydrogen. Honda plans to start leasing the FCX Clarity this summer for $600 per month. The only problem: Since there is no real hydrogen infrastructure available yet, leases will be made in limited numbers, and only in the Los Angeles area, where a handful of hydrogen filling stations are accessible.

Strategic Selling Points

Ford argues that to really make a dent in fuel consumption, automakers need mass-market strategies, not a sprinkling of high-profile niche fuel cells or hybrids.

That’s why a cornerstone of its sustainability strategy is a new engine technology called EcoBoost, which combines smaller direct-injection engines with turbo-charging. To explain its strategy, Ford is showing the Ford Explorer America, a concept vehicle that knocks 20-30 percent off the fuel consumption of today’s V6 Explorer. The concept also represents a new direction for Explorer — a switch from a truck-based chassis to a unibody, car-like platform.

Clean diesels are finally making their way to the U.S. in the second half of the year, but none will be as powerful as the Audi R8 diesel concept car. The German luxury carmaker wants to show skeptics that it is possible to have powerful sports cars with diesel engines. The concept is powered by a 500-hp, 6.0-liter turbo-diesel engine.

Nissan is also contemplating a diesel engine for a concept, called the Forum, that shows what its next-generation minivan might look like. Nissan tried once before to make a minivan “cool” with its aggressive-looking Quest, but sales disappointed, mostly because of quality issues.

The Forum concept isn’t quite so radical, but it still offers some new approaches to family transportation. Its trackless sliding doors give a sleeker look, and swiveling second-row seats provide the ability to view a ballgame through the wide-open side doors. Two entertainment zones — one for parents and one for kids — are linked by a “time-out" switch that lets Mom or Dad silence the entire vehicle when needed.

In Pictures: Cars Of The Future