The Geneva Motor Show is a showcase for bizarre concept cars and impractically tiny fuel-sippers that will never come to this U.S. because of their unsuitability for our driving conditions. One of this year's debuts, the Audi A3 Sportback g-tron, follows that tradition of not coming to the U.S.
This is unfortunate because the g-tron would be an ideal car for American drivers. That's because it runs on natural gas. A challenge Compressed Natural Gas-powered cars - like the currently available Honda Civic CNG - have faced is a short driving range owing to the fact that gaseous natural gas isn't as energy-dense as liquid gasoline. That makes it harder to carry enough fuel for long intervals between refills. The g-tron features a pair of cutting-edge technology natural gas tanks that expand the car's driving range to a very practical 250 miles.
And then, in case there is no natural gas station nearby, the owner can still drive on gasoline power for another 460 miles if needed. That pretty well settles the questions of range and practicality. America is poised to become the world leader in natural gas production, and as a result of this fuel glut, natural gas now costs a fraction the price of gasoline.
We have a complete natural gas distribution infrastructure already in place and need only to expand the retail sales outlets to make fueling cars with natural gas as convenient as buying gasoline. Not only is natural gas cheaper than gasoline and domestically sourced - so no money goes to unstable or overtly antagonistic oil-producing countries - but it is also cleaner. Natural gas cars produce effectively zero smog-forming pollution and a sliver of the carbon dioxide created by burning more chemically complex gasoline molecules.
Natural gas molecules are lean, so burning them is clean. Audi put some clever engineering into the g-tron to perfect natural gas driving. Each of the two carbon fiber tanks weighs nearly 60 pounds less than a conventional tank and it holds gas compressed to 3,000 psi. The fuel system features a two-stage pressure regulation that steps that tremendous pressure down to a range between 75 and 135 psi (depending on engine speed) for the fuel injectors.
The fuel fillers for both the natural gas tanks and the gasoline tank are under the same fuel door, so drivers don't have to remember which filler they are using depending on the fuel. In addition to providing a safety margin for driving in areas where natural gas stations are sparse, having gasoline aboard also aids startup in very cold weather. If it is very cold then the g-tron starts on gasoline and switches to natural gas when it has warmed up.
Switch-over between fuels is automatic and seamless, whether it is for cold starts or because the driver depleted the car's supply of natural gas. In other respects, the Audi g-tron is a conventional A3, with a 110-horsepower 1.4-liter turbocharged four-cylinder engine that produces a top speed of 118 mph and 0-60 acceleration of 11 seconds. Performance is the same on either form of gas.
The g-tron is based on the hatchback version of the A3. Hopefully, Audi can one day turn its attention to bringing a g-tron to the world's largest natural gas producer.