Amid tightening emissions regulations, car manufacturers are looking for new ways to make their engines more efficient. Volkswagen has used this year's Vienna Motor Symposium to unveil a range of new technologies aimed at eking better mileage out of gasoline, hybrid and electric powertrains alike.
On the gasoline front, Volkswagen is searching for better efficiency through clever coasting capabilities built into its DSG gearboxes. At any speed up to 130 km/h (81 mph), the system will completely switch the engine off and decouple the gearbox as the vehicles coasts after the foot is taken of the throttle. According to Volkswagen, this can help shave 0.4 l/100 km (3 mpg) from the fuel use sticker, compared to 0.2 l/100 km (1.5 mpg) you get from current coasting setups.
To support its new, improved coasting function, Volkswagen has added a small lithium-ion battery to the existing 12-volt vehicle electronic setup. The little lithium-ion unit steps in to power all the requisite in-cabin electric systems when the engine is switched off, rather than leaning on the old-fashioned lead-acid battery. When the driver needs some power under their right foot, the engine can be restarted using the clutches in the DSG gearbox, the starter motor or a combination of the two.
Moving beyond gasoline power, VW is working to develop a compressed natural gas (CNG) powertrain for the next-generation Polo. Volkswagen isn't alone in trying to make CNG happen – Audi is one of the biggest proponents, and the fuel is growing in popularity among trucking companies – but no one has really slotted it into a reasonably-priced family hatch.
Even if it comes from fossil sources, Volkswagen says CNG is better for the environment than gasoline or diesel from "well-to-wheel" as it burns cleaner. That advantage can be furthered if the gas is derived from renewable sources, like industrial waste, landfills or wastewater treatment plants. VW says it's currently in talks with energy suppliers, gas companies and government agencies to put sustainably sourced CNG on the map.
Because the fuel isn't particularly widespread, the three-cylinder TGI engine on show in Vienna will run on both CNG and gasoline. Regardless of fuel, it produces a handy 66 kW (89 hp) of power and, thanks to a clever catalytic converter that works efficiently from cold, low emissions. Then again, we've heard that claim before...
Electric power has been thrust into the spotlight recently, with a string of very pretty battery-powered concepts signaling VW's intent to significantly expand its range of EVs. For now, that electric range is limited to the e-Golf, which has been boosted to deliver 100 kW (134 hp) of power and 290 Nm (214 lb-ft) of torque. Thanks to improvements in battery cell technology, the under-floor pack has been boosted from 24.2 kWh to 35.8 kWh for a range of 300 km (186 mi).
The new VW powertrain technology was on show at the Vienna Motor Symposium, which wrapped up last week.