Volkswagen has developed a new engine that runs on both petrol and compressed natural gas.
The Passat TSI EcoFuel uses a 1.4-litre engine that is turbocharged and supercharged to give 148bhp.
It has also been tuned for low emissions and fuel consumption, providing a range of more than 490 miles between petrol and gas tanks.
The gas is stored in three tanks underneath the boot floor with a total capacity of 22kg.
In normal driving, the gas is used at a rate equivalent to 54.2mpg and the driver can switch between petrol and gas at will.
The Passat TSI EcoFuel meets all forthcoming emissions regulations and still manages 0-62mph in 9.7 seconds and a top speed of 130mph.
This Passat will be on sale in Europe before the end of 2008, but it has not been confirmed if the car will come to UK due to the shortage of outlets selling compressed natural gas.
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