TSI combines with natural gas to mix performance with economy

In unveiling the Passat Estate TSI EcoFuel concept – a car powered by either natural gas or conventional petrol – at the Geneva Show, engineers have combined the seemingly contradictory virtues of performance and economy.

The Passat Estate TSI EcoFuel is powered by a 1.4-litre TSI 150 PS engine running on either natural gas or petrol. The engine features both a supercharger and a turbocharger operating sequentially to provide relatively high power outputs from a small capacity engine. In order to allow the engine to cope with the additional loading encountered through the burning of natural gas rather than gasoline, significant changes are made. The valves, piston rings and the pistons themselves are all uprated to cope while the turbocharger has also been replaced with a smaller unit. Controlling the switch between conventional fuel and natural gas is a new engine management computer.

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.

The result is a non-diesel vehicle that meets the Euro 5 standards, greater economy and lower emissions. In addition, 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. In normal conditions the vehicle consumes 5.2 kg of natural gas every 100 km.

In mainland Europe the vehicle will be introduced in both saloon and estate bodystyles before the end of the year. Sales of the vehicle in the UK are yet to be confirmed.

Timing

Geneva Motor Show marks the world debut of the Passat TSI EcoFuel concept

Sales in mainland Europe set to commence before the end of the year for both saloon and estate versions of the Passat

UK sales yet to be confirmed

Key facts

Developed by Volkswagen engineers to demonstrate the feasibility of a TSI engine running on natural gas and its inherent benefits in markets in which the fuel is supported

Draws on the virtues of the 1.4-litre TSI engine fitted with both a supercharger and a turbocharger and combined with the ability to run on either conventional fuel or natural gas

In order to allow the engine to cope with the additional loading encountered through the burning of natural gas rather than gasoline, significant changes are made

The changes extend to the valves, piston rings and the pistons themselves which are all uprated to cope while the turbocharger has also been replaced with a new unit

Controlling the switch between conventional fuel and natural gas is a new engine management computer

In normal use the vehicle consumes 5.2 kg of natural gas every 100 km

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

The resulting vehicle is both extremely efficient and produces fewer emissions when compared to a conventionally-fuelled Passat Estate TSI. Despite these gains the engine still produces 150 PS, allowing it to accelerate from 0 to 62 mph in 9.7 secs before reaching a top speed of 130 mph

Visual changes to distinguish the Passat TSI EcoFuel include a pair of fuel gauges – one for each fuel tank – and a set of discreet ‘EcoFuel’ badges mounted on the outside of the vehicle