Volkswagen has equipped its natural gas models of the Polo TGI and Golf TGI with a third natural gas tank made of specially coated, high-strength steel. The Golf’s tank has a volume of 23 liters and increases the total CNG tank volume to 115 liters, or 17.3 kg respectively, which offers a range of up to 422 kilometers in WLTP.
On the Polo with 1.0 three-cylinder engine (66 kW / 90 PS) the additional tank carries 16.5 liters and extends the natural gas storage to 91.5 liters in total, or 13.8 kg respectively, meaning that the Polo can travel up to 368 kilometers on CNG in WLTP. As a back-up, both models come with a gasoline tank – albeit a much smaller version.
Polo TGI with new tank system.
For improved driving dynamics and efficiency, the Golf TGI comes with a new 1.5 liter four-cylinder engine, which is powerful, efficiency and environmentally friendly. Proof of this comes from its fuel consumption of just 3.6 kg – 3.5 kg natural gas over 100 kilometers, and CO2 emissions of just 98–95 g/km.
The new 1.5-liter TGI engine in the Golf uses the TGI Miller combustion process with a high compression ratio of 12.5:1, to increase efficiency and decrease CO2 emissions.
A turbocharger with variable turbine geometry increases the boost pressure, adding more air into the cylinders. This allows the 1.5-liter TGI engine to accelerate powerfully at any time from low speeds.
Driving in CNG mode produces around 25% fewer CO2 emissions than with gasoline. An even better CO2 balance can be achieved by fueling with biomethane or e-gas. Biomethane is extracted from plant residues; e-gas is produced from surplus green energy (power-to-gas), which are added to the fuels.
Furthermore, natural gas generally combusts with less emissions than gasoline or diesel. The exhaust gas contains significantly less carbon monoxide and NOx, while the fraction of soot or fine particles is minimal.