Thanks to the TGI Miller combustion process and the variable turbine geometry (VTG) of the turbocharger, the Golf Variant TGI’s 1.5-litre four-cylinder petrol engine is even more efficient and responsive than its predecessor. It delivers 96 kW (130 PS) and boasts a torque of 200 newton metres. With the petrol tank reduced in size to 9 litres (for a Golf Variant TGI, that corresponds to a range of approximately 200 kilometres) and now serving merely as a backup, this is referred to as a quasi-monovalent drive concept. In other words, the range with natural gas alone has increased by around 80 kilometres, enabling routes of up to 440 kilometres (based on WLTP) with natural gas alone.
The three natural gas tanks have a combined volume of 115 litres, which corresponds to a total weight of 17.3 kilograms. The tanks are made from carbon fibre-reinforced plastic (CFRP) or from metal.
The CO2 emissions of a natural gas vehicle are much lower than those of a comparable vehicle with a conventional engine, as combustion of compressed natural gas (CNG) releases around 25 per cent less CO2 than combustion of petrol. The reason for this is the low percentage of carbon in natural gas. Thanks in part to the innovative lambda split process, natural gas also burns extremely cleanly: the exhaust contains much less carbon monoxide and nitrogen oxide (NOX), resulting in minimal soot and fine dust. If you fill up your vehicle with biomethane or e-gas, you can minimise your emissions even further, as biomethane is derived from residual plant matter, and e-gas from excess green energy (power to gas). Both can be added to fuels or are available as pure biofuels.
Driving with natural gas is also comparably cheaper in just about all countries. In Germany, natural gas is around 20 per cent cheaper than diesel and as much as 40 per cent cheaper than petrol. And that’s despite the fact that natural gas contains much more energy. For comparison: one kilogram of CNG corresponds to around 1.3 litres of diesel or 1.5 litres of petrol.
In Germany, the number of natural gas vehicles is expected to reach one million by 2025, with some 100,000 natural gas vehicles already registered. For this to work, the product portfolio needs to be expanded and the network of filling stations in Europe increased to 2,000 – also by 2025.
In addition to the eco up! and TGI models of the Polo, Golf, Golf Variant the Volkswagen Group also already offers an extensive range of 14 CNG vehicles.