Petrol or diesel - which is cheaper? - What does the future hold?

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Diesel or petrol?
Diesel or petrol?
in spite of headline-grabbing technologies such as hybrid, hydrogen and electric power, there’s plenty of life in traditional engines yet.

Diesel engines typically give up to 30% better fuel economy than comparable petrol units. With many European governments now imposing CO2-related taxes – and CO2 output is directly related to fuel consumption – European drivers are by far the most enthusiastic supporters of diesel.

However, diesels also produce more nitrous oxides and hydrocarbons – waste products that have been linked with cancer, heart disease and increased rates of asthma. Most of this waste can be purified with filters and chemicals – and will have to be with the Euro VI emissions regulations due in 2014 – but this is costly.

The petrol engine, meanwhile, is making a comeback. With direct fuel injection and a turbocharger, petrol engines can be made smaller, lighter and more efficient, with no loss of performance. John Hilton, chairman of the automobile division of the Institution of Mechanical Engineers says: ‘Good diesels are 35% efficient, while petrols are around 27%. With more use of technology such as direct injection and turbocharging we can expect to close that gap dramatically, probably by half. That will be enough in most markets to make the diesel or petrol choice difficult to call.’

Dr Ulrich Hackenberg, head of research and development for Volkswagen, says there is scope to get much more out of both petrol and diesel engines. ‘We have already started with downsizing and we see some possibilities to go a little bit further forward – possibly to three cylinders with some form of [hybrid] electrification,’ he says. ‘We are working very intensively on improving classical technologies.’

What Car? says
You may love the way a certain engine behaves, and be willing to pay extra for it, or you may place the financial bottom line at the top of your list of desires, and driving pleasure of secondary concern. Whatever your needs, a bit of maths and a few test drives are crucial when it comes to choosing your next car. Do the groundwork properly and you’ll end up with the perfect car, be it diesel or petrol, for you.

Click here for a larger view of our petrol vs diesel price comparison chart

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