In response to ever more stringent CO2 emissions regulation, European carmakers are beginning to roll out vehicles fueled by compressed natural gas (CNG). The latest and possibly most advanced of these is the Audi A3 g-tron, which sounds like it might be either a knockoff Transformer or maybe Young Jeezy’s robotic hype man. But it’s just a car. Based on the five-door A3 Sportback, it packs a 110-hp 1.4-liter TFSI engine that produces 148 lb-ft of torque and can combust both regular gasoline and CNG. The g-tron switches to gasoline operation automatically when the onboard CNG runs low, but the switch also can be triggered manually.
The g-tron is down 12 horsepower versus the regular A3 1.4 TSI. To allow CNG operation, Audi altered the turbocharger, cylinder head, injection system, and the catalytic converter. This A3 won’t be for everyone, though, most of all us: The sprint from 0 to 62 mph takes a leisurely 11 seconds and top speed is 118 mph. But then again, it is very efficient: It consumes just 7.7 pounds of CNG per 62 miles. That’s exactly one-quarter of the total capacity of the two CNG tanks, which are positioned below the cargo floor. The A3 Sportback g-tron’s range on CNG is around 250 miles, with another 560 miles enabled by tapping the gasoline tank. That’s a lot of distance between stops, and refueling is said to take just minutes—not counting the time spent hunting for a CNG station, of course.
CNG tanks can often be heavy; not so with the g-tron’s, which both feature an Audi-engineered “matrix” design constructed from three layers. The outer layer consists of a glass-fiber reinforced polymer, the middle layer uses carbon fiber, and the inner layer is made from gas-tight polyamide polymer. As a result, each tank is said to cut a whopping 60 pounds from a similarly sized regular CNG tank.
The instrument cluster now features two gauges positioned to the lower right sides of both the tachometer and the speedometer; they report on the fuel level in each of the tanks. The CNG filler port is placed right next to the one for gasoline, and they share the same fuel door. The engine cover now features “g-tron” branding. That’s it as far as visible changes go, and the seamless integration of CNG hardware certainly sets the g-tron apart from aftermarket conversions.
Audi is serious about its g-tron strategy, and makes some ado about its proprietary e-gas—it’s synthetic methane produced in controlled environments and with energy from “renewable sources.” Audi claims that when the g-tron is powered by e-gas, “no more CO2 is released than was chemically input into its production beforehand,” which is interesting because such a claim, if true, would reduce fuel consumption to an issue of cost among end users, not of presumed pollution.
While not all models will be available everywhere, the A3 lineup will eventually encompass three- and five-door hatches, a sedan, a convertible, and S3 and RS3 high-performance models. Powertrains will include conventional gas and diesel engines, as well as an e-tron plug-in hybrid—previewed as a concept at this same Geneva show—and this g-tron CNG system, which will be launched in Europe in late 2013. There is no word yet on pricing, or on a US market launch, although we’re not holding our breath.
MARC URBANO, THE MANUFACTURER