A fuel efficiency device fails to match claims of 30% effectiveness in tests by engineers
A conversion kit claiming to allow vehicles to run more efficiently using water does not work, a BBC investigation has discovered.
Hydrofuel devices are widely available on the internet, with customers paying up to £500 to get their car converted.
Companies selling them claim they are environmentally friendly and will make vehicles up to 30% more fuel efficient.
But Inside Out East tested one device sold by a Norfolk company at an industry testing centre and found it made no difference.
The device tested was supplied by Hydrofuel-Systems in Aylsham, Norfolk.
Its main component is a stainless steel vessel containing water and electrodes. It generates bubbles of oxygen and hydrogen gas by electrolysis, using an electrical current.
I'm afraid for fuel economy, there is no improvement
The device is fitted under the bonnet of the car and draws its power from the car battery.
The mixture of oxygen and hydrogen is piped into the air intake of the engine and is supposed to add to the conventional fuel.
Graham Mace, from Norfolk, was keen to clean up his Range Rover's green credentials. He was delighted when he found the device on the internet and was told he would save up to 30% on diesel.
He bought one for £295 and logged fuel consumption over a period of three months but found no improvement.
He then tried several modifications suggested by Hydro-Fuel Systems but after spending around £700 in total, he still had not saved a penny in fuel.
The BBC had a car fitted with a hydrofuel device by Hydrofuel-Systems.
It was taken to Millbrook Proving Ground in Bedfordshire, where a series of tests were carried out.
Withdrawn from sale
The conclusion of the government-approved tests was that the device had no effect at all.
Neil Fulton, manager powertrain engineering at Millbrook, said: "We have conducted tests, over many different driving conditions, in the laboratory. I'm afraid for fuel economy, there is no improvement."
When confronted with the evidence, Steven Cordner of Hydro-Fuel Systems claimed the system worked but admitted he had no proof to show us. He said they had stopped selling the product.
The devices are still widely available on the internet, with prices ranging from £100 to £500.
Nick Collings of Cambridge University, has studied the claims made for the devices and concluded that they cannot work. In fact he says they make cars on average 2% less efficient.
"With these devices, it takes more gasoline to generate the electrical energy needed to create the hydrogen, than it can contribute back to the engine."
Steve Cordner, director of Hydrofuel-Systems refused to be interviewed but told the BBC that the systems did work. He also said that they were withdrawing them from sale.
The full report can be seen on Inside Out (BBC East) on BBC One at 1930 BST on Monday, 19 October.
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