Economical dual-fuel TSI concept from Volkswagen

In the quest for making the internal combustion engine go further on less fuel, we’ve seen many different combinations of normal and forced aspiration and alternative fuels, but this is a new take on combining the seemingly contradictory virtues of performance and economy. Volkswagen showed a new concept car in Geneva a few hours ago that uses both natural gas and petrol. That’s not new, but it’s the first time it has been combined with the VW TSI engine which uses both a supercharger and a turbocharger operating sequentially to provide high power (150 bhp), great economy, exceptional range and meet Euro 5 emission standards from a small capacity (1.4 liter) engine.

With a top speed of 130 mph and the capability to accelerate from 0 to 62 mph in 9.7 seconds, the Passat Estate TSI EcoFuel remains viable for everyday use and in most driving conditions the vehicle consumes 5.2 kg of natural gas every 100 km.

In order to allow the engine to cope with the additional loading encountered through the burning of natural gas rather than gasoline, significant changes have been made to the valves, piston rings and the pistons and a smaller turbocharger is used. The whole lot is orchestrated by a new engine management computer controlling everything the engine does, including orchestrating a seamless switch between fuels.

The natural gas is stored in a trio of tanks with a combined capacity of 22 kg mounted beneath the boot floor. This is supplemented by a 31-litre tank for conventional petrol. Between the two tanks the Passat Estate TSI EcoFuel is afforded a theoretical range of over 490 miles.

They’re calling it a concept, but in a bullish move, have announced the vehicle will be introduced in mainland Europe in both saloon and estate bodystyles before the end of the year.