10-04-2017, 08:13 PM
A water-fuelled car is an automobile that hypothetically 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 websites. The claims for these devices have been found to be pseudoscience and some were found to be tied to investment frauds.
These vehicles may be claimed to produce fuel from water on board with no other energy input, or may be a hybrid claiming to derive some of its energy from water in addition to a conventional source (such as gasoline).
Water is fully oxidized hydrogen. Hydrogen itself is a high-energy, flammable substance, but its useful energy is released when water is formed. Water will not burn. The process of electrolysis can 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 waste 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 or second law of thermodynamics.
What water-fuelled cars are not
A water-fuelled car is not any of the following:
Water injection which is a method for cooling the combustion chambers of engines by adding water to the incoming fuel-air mixture, allowing for greater compression ratios and reduced engine knocking (detonation).
The hydrogen car, although it often incorporates some of the same elements. To fuel a hydrogen car from water, electricity is used to generate hydrogen by electrolysis. The resulting hydrogen is an energy carrier that can power a car by reacting with oxygen from the air to create water, either through burning in a combustion engine or catalyzed to produce electricity in a fuel cell.
Hydrogen fuel enhancement, where a mixture of hydrogen and conventional hydrocarbon fuel is burned in an internal combustion engine, usually in an attempt to improve fuel economy or reduce emissions.
Extracting energy from water
According to the currently accepted laws of physics, there is no way to extract chemical energy from water alone. Water itself is highly stable it was one of the classical elements and contains very strong chemical bonds. Its enthalpy of formation is negative (-68.3 kcal/mol or -285.8 kJ/mol), meaning that energy is required to break those stable bonds, to separate water into its elements, and there are no other compounds of hydrogen and oxygen with more negative enthalpies of formation, meaning that no energy can be released in this manner either.
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 useful energy released, this cannot be used to produce net energy.
