Anyone who already drives a CNG vehicle (CNG = compressed natural gas) also benefits from comparably low fuel prices in many countries. In Germany, for example, the cost saving compared to a diesel vehicle is currently 20 per cent, or 40 per cent compared to a petrol vehicle. Understandably, drivers of natural gas vehicles only want to use petrol in exceptional cases. Volkswagen has therefore 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 litres and increases the total CNG tank volume to 115 litres, or 17.3 kg respectively, which offers a range of up to 422 kilometres in WLTP.
On the Polo with 1.0 three-cylinder engine (66 kW / 90 PS) the additional tank carries 16.5 litres and extends the natural gas storage to 91.5 litres in total, or 13.8 kg respectively, meaning that the Polo can travel up to 368 kilometres on CNG in WLTP. As a back-up, both models come with a petrol tank – albeit a much smaller version.
For improved driving dynamics and efficiency, the Golf TGI comes with a new 1.5 litre 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 kilometres, and CO2 emissions of just 98–95 g/km. The new 1.5-litre TGI engine in the Golf uses the innovative 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-litre TGI engine to accelerate powerfully at any time from low speeds.
Driving on natural gas is not only good for your wallet, it is also good for the environment. Compared to petrol or diesel, natural gas contains a significantly higher amount of energy and a lower carbon fraction. This means that driving in CNG mode produces around 25 per cent fewer CO2 emissions than with petrol. What is more, natural gas generally combusts with less emissions than petrol or diesel. The exhaust gas contains significantly less carbon monoxide and nitrous oxide (NOx), while the fraction of soot or fine particles is minimal.