Poorly standardised tests, an obvious scam and chip fat...

Poorly standardised tests, an obvious scam and chip fat...Russ Swan delves into the mire of fuel economy

Even though the price of fuel has come down a bit over the last several months, filling the tank still causes a sharp pain in the wallet. With no end to austerity in sight, a new and inexpensive technique to reduce fuel bills has to be worth investigating, doesn't it?

There's no shortage of options for the modern fuel miser to consider. Those with deep pockets might consider one of the new hybrid vehicles, some of which make extraordinary claims for fuel economy. The capital cost is a bit steep for me, but a car that does 140 miles per gallon while seating five adults in comfort seems almost worth its £30,000 asking price.

Or it would, if the reported economy was real. In science we all understand that extraordinary claims require extraordinary proof. It is a basic tenet of advertising that you can claim just about anything you like until someone goes to the bother of challenging it through official channels, and even then nobody will notice the correction.

Official car fuel economy figures are hopelessly unrealistic. The standardised tests were drawn up by (who else?) motor manufacturers, and systematically overstate the mileage that can actually be achieved.

But standardised tests are what we all strive for in the laboratory. Standardised tests are good, as long as they are appropriately interpreted. In the case of motoring fuel economy, appropriate interpretation means ignoring the units and treating the results as dimensionless numbers. Values can be compared, but they don’t really mean anything in absolute terms.

Miles per gallon is meaningless anyway. Here in the semi-metric UK we may still measure distance based on 1000 paces of a Roman centurion, but when did you last buy petrol by the gallon?

But I digress. I'm stuck with an ageing car which uses too much fuel, whatever the measure, I can’t afford to buy a plug-in hybrid. A friend converted an old diesel car to run on waste oil from a chip shop, but reports that it is now getting hard to find a supply of this once-free fuel. She also carried around with her a permanent fog of fragrance – eau de battered cod, we called it – which soon became a bit tiresome.

There are scientifically-proven ways to improve mileage. Proper vehicle maintenance – filters and tyre pressures mainly – make an appreciable difference. Equally worthwhile dividends come from not driving like an idiot, but that can harder for some of us to maintain.

Load reduction also has its benefits, which is one of the excuses car makers use for not giving you a spare wheel any more. That tin of squirt-in tyre goo might be next to useless when you get a puncture, but its real benefit is in shaving 20kg off your dead weight and taking maybe 15g of carbon out of every mile you drive. I even saw some advice to van drivers recently that they could improve their mileage by carrying less stuff around with them. This seemed to fundamentally misunderstand what a van is actually for.

What's really needed is some new technological breakthrough to help us make the most of our existing vehicles. Surely in this age of engineering wonder, where we all carry a supercomputer in our pockets and can video conference to the other side of the globe in an instant, there must be something to help make petrol go a bit further?

And then somebody showed me the Fuel Shark. This 'break-through patent pending invention' will, apparently, increase your mileage 'just by plugging it into your cigarette lighter socket'. Not only that, but also 'more horsepower, better acceleration, longer battery life, and cleaner emissions'. What's not to like?

There are a couple of clues to the American provenance of the device in the text – references to gas and dollars in particular. And European car makers stopped fitting their vehicles with cigarette lighters a decade or two ago – nowadays they fit an identical component known as a 12V power outlet.

But what of the device? Apparently half a million satisfied customers have saved 15.3% of their fuel by simply plugging it in and driving normally. It contains 'electronic components' which 'regulate voltage', it says here. In other words, it’s a modest capacitor, resistor, and LED.

At the time of writing, the shop on a popular internet auction site showed 84 sales. And this simple statistic tells us something of much wider significance.

There had been some concern among sociologists that the events of the last month would result is a severe shortage of credulousness among the UK population. This demonstrates that there is no cause for alarm, as at least 84 people have been gullible enough to part with actual cash money for this obvious scam. Sighs of relief can be heard throughout Whitehall.