The greenest petrol car in 2012?

Petrol engines are traditionally more expensive to run than diesels because they use more fuel per mile driven.

However, Mazda has designed a new 1.3-litre petrol engine, named Skyactiv, which is capable of returning 85mpg – nearly 10mpg more than the most efficient diesel Ford Fiesta.

It is also road tax free because of expected CO2 emissions of 99g/km, making it one of the few petrol cars to be exempt from the yearly charge.

The car, which is based on the new, updated Mazda2, has already won a 2012 Car of the Year ‘Special Award’ in its home country of Japan after a 2011 launch and more recently has been named Car of the Year by the Japan Committee.

The Mazda2 is a three- or five-seat small hatchback taking on the likes of the Vauxhall Corsa and Ford Fiesta in the lucrative supermini sector.

The new Mazda2 will not be the only cars to benefit from Mazda’s Skyactiv technology, which includes new engines, new transmissions and even chassis and lightweight materials to reduce fuel consumption.

The Mazda3 hatchback and the all-new Mazda CX-5 crossover, set to be launched in the UK in 2012, will use the technology.

The introduction of more frugal petrol and diesel engines is part of Mazda’s plan to shun electric vehicles in favour of greener conventional engines over the next five years.

New Mazda2 Skyactiv prices have not been revealed. Standard Mazda2 models start from £10,305 in the UK for the three-door 1.3-litre petrol engine.

The current generation Mazda2 is available in Mazda dealerships now. It will include the new Skyactiv engines in 2012.