In May this year, during the Wörthersee GTI meet, Audi revealed a near-production variant of its A5 Sportback model, equipped with gasoline engine running on compressed natural gas. It is now making the transition to a production vehicle, already available to order at the German brand’s dealerships.
Power comes from a 2.0-liter TFSI bivalent motor producing 170 horsepower (125 kilowatts) and 199 pound-feet (270 Newton-meters), and running on one of three fuels - Audi e-gas, conventional CNG (compressed natural gas), or gasoline. The unit is based on the standard gasoline-burning 2.0 TFSI but works on an “innovative combustion principle.” Audi promises the premium liftback will need an average of 3.8 to 4.2 kilograms CNG per 62 miles (100 kilometers) with corresponding CO2 emissions of 102 to 114 grams per kilometer.
Joining Audi’s CNG range is also the A4 Avant G-Tron which is powered by the same 2.0-liter engine. Fuel consumption is almost identical at 3.8-4.4 kg/62 miles (kg/100 km) and 0-62 miles per hour (0-100 kilometers per hour) acceleration takes 8.5 seconds. When running on CNG, the wagon can reach a maximum speed of 139 mph (223 kph).


The automaker says both the A5 Sportback G-Tron and A4 Avant G-Tron can travel up to 310 miles (500 kilometers) on CNG measured by the NEDC cycle. Once the pressure in the tank, made of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP), falls to 10 bar (0.6 kilograms of gas), the engine automatically switches to gasoline operation. This delivers additional range of more than 280 miles (450 km) for a grand total of 590 miles (950 km).
Audi will bring the A4 Avant G-Tron at the Frankfurt Motor Show in September to showcase its CNG technology. Customers interested in this eco-friendly solution can already order both models with prices in Germany starting at €40,800 for the A5 Sportback ($47,930 at the current exchange rates) and €40,300 ($47,355) for the A4 Avant.
Source: Audi
Gallery: 2017 Audi A5 Sportback G-Tron
Audi is offering its customers two sustainable alternatives in the midsize category: the new A4 Avant g-tron and the new A5 Sportback g-tron. Both models are powered by a bivalent 2.0 TFSI engine developing 170 hp. Like the A3 Sportback g-tron that is already on the market, they can run on a choice of the climate-friendly fuel Audi e-gas, conventional CNG (compressed natural gas) or gasoline. Customers can now order both models from dealers.
A4 Avant g-tron: CNG consumption in kg/100 km: 4.4 - 3.8*; combined fuel consumption in l/100 km: 6.5 - 5.5*; combined CO2 emissions in g/km (CNG): 117 - 102*; combined CO2 emissions in g/km (gasoline): 147 - 126*
A5 Sportback g-tron: CNG consumption in kg/100 km: 4.2 - 3.8*; combined fuel consumption in l/100 km: 6.3 - 5.6*; combined CO2 emissions in g/km (CNG): 114 - 102*; combined CO2 emissions in g/km (gasoline): 143 - 126*
A3 Sportback g-tron: CNG consumption in kg/100 km: 3.6 - 3.3*; combined fuel consumption in l/100 km: 5.5 - 5.1 *; combined CO2 emissions in g/km (CNG): 98 - 89*; combined CO2 emissions in g/km (gasoline): 128 - 117*
Sporty, climate-friendly and economical – the new Audi A4 Avant g-tron and A5 Sportback g-tron meet all those requirements. At the same time they offer an impressive degree of everyday usability. They have a range of 950 kilometers (590.3 mi), of which up to 500 kilometers (310.7 mi) can be covered in the CNG mode. The price for the A4 Avant g-tron is EUR 40,300 in Germany. The A5 Sportback g-tron starts at EUR 40,800. Audi is presenting its g-trontechnology at the IAA in Frankfurt in September.
A 2.0 TFSI engine powers both the A4 Avant g-tron and the A5 Sportback g-tron. It develops 125 kW (170 hp) and achieves torque of 270 Nm (199.1 lb-ft). The newly developed engine is based on the gasoline-powered 2.0 TFSI with innovative combustion principle.
It is highly economical: Over the standard cycle the A4 Avant g-tron with S tronic uses just 3.8 kilograms of gas per 100 kilometers, with CO2 emissions of 102 grams per kilometer (164.2 g/mi) (in gasoline mode: 5.5 liters per 100 kilometers (42.8 US mpg) and 126 grams of CO2 per kilometer (202.8 g/mi)). The figures for the A5 Sportback g-tron with S tronic are almost as good: In the gas mode, it too manages on just 3.8 kilograms per 100 kilometers, and achieves CO2emissions of 102 grams per kilometer (164.2 g/mi). In gasoline mode, these figures are 5.6 liters per 100 kilometers (42.0 US mpg) and 126 grams of CO2 per kilometer (202.8 g/mi).
The drive unit’s high efficiency means low costs of ownership: Fuel costs compared with an equivalent gasoline engine are much lower, at around four euros per 100 kilometers (62.1 mi) (Germany, as at: August 2017). The lower CO2 emissions also mean owners pay less in motor vehicle tax. In addition to being very economical to run, the new g-tron models have an extremely clean combustion process. But this does not make them any less fun to drive. In conjunction with the manual six-speed transmission, the A5 Sportback g-tron accelerates from a standstill to 100 km/h (62.1 mph) in just 8.5 seconds (A4 Avant g-tron: 8.5 seconds). Its top speed is 226 km/h (140.4 mph) (A4 Avant g-tron: 223 km/h (138.6 mph)).
Thanks to their bivalent design, the g-tron models can cover up to 500 kilometers (310.7 mi) on natural gas in the NEDC cycle. When the pressure in the tank falls below 10 bar with about 0.6 kilogram (1.3 lb) of gas remaining, the engine management automatically switches to gasoline operation. This makes an extra range of more than 450 kilometers (279.6 mi) available. The high-strength, safe gas tanks made from carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) are located beneath the rearward structure. They store 19 kilograms (41.9 lb) of gas at a pressure of 200 bar. Both models have a full-size luggage compartment: There is 415 liters (14.7 cu ft) of luggage capacity in the A4 Avant g-tron, and 390 liters (13.8 cu ft) in the A5 Sportback g-tron.
The g-tron models are especially eco-friendly when running on Audi e-gas. This synthetic fuel is produced using renewable energy from water and CO2 or from organic residual materials such as straw and plant clippings. During its production, Audi e-gas binds exactly the amount of CO2 emitted by the car. Audi offers this fuel for three years as a standard feature to customers ordering a g-tron model by May 31, 2018. They can fill up their g-tron model at any CNG filling station and pay the regular price. By feeding the computed volume of Audi e-gas into the natural gas grid, Audi ensures the green benefits of the program, including the corresponding reduction in CO2 emissions. With this deal, Audi is reducing the CO2emissions of the g-tron fleet when running on gas by up to 80 percent**. Customers no longer require a special fuel card. Instead, Audi computes the volume automatically based on surveys and service data from the cars. TÜV Süd, a German testing and certification authority, monitors and certifies the process. Audi g-tron customers receive a document that confirms their car will be supplied with Audi e-gas and informs them about the certification.