Water-fuelled car

Water-fuelled car - Wikipedia, the free encyclopedia

A water-fuelled car is a hypothetical automobile that derives its energy directly from water. Water-fuelled cars have been the subject of numerous international patents, newspaper and popular science magazine articles, local television news coverage, and the Internet. The claims for these devices have been found to be incorrect and some were found to be tied to investment frauds.[1][2][3][4] These vehicles may be claimed to produce fuel from water on board with no other energy input, or may be a hybrid of sorts claiming to get energy from both water and a conventional source (such as gasoline).

The process of electrolysis, discussed below, would split water into hydrogen and oxygen, but it takes as much energy to take apart a water molecule as was released when the hydrogen was oxidized to form water. In fact, some energy would be lost in converting water to hydrogen and then burning the hydrogen because some heat would always be produced in the conversions. Releasing chemical energy from water, in excess or in equal proportion to the energy required to facilitate such production, would therefore violate the first and/or second laws of thermodynamics.

According to the currently accepted laws of physics, there is no way to extract chemical energy from water alone. Most proposed water fuelled cars rely on some form of electrolysis to separate water into hydrogen and oxygen and then recombine them to release energy; however, because the energy required to separate the elements will always be at least as great as the energy released, this cannot be used to produce net energy.

A number of websites exist promoting the use of oxyhydrogen (which they often refer to as "HHO"), selling plans for do-it-yourself electrolysers or entire kits with the promise of large improvements in fuel efficiency. According to a spokesman for the American Automobile Association, "All of these devices look like they could probably work for you, but let me tell you they don't."

In addition to claims of cars that run exclusively on water, there have also been claims that burning hydrogen or oxyhydrogen in addition to petrol or diesel fuel increases mileage. Whether such Hydrogen On Demand systems actually improve emissions or fuel efficiency is debated.[40]