You may be scratching your head at this point and rightly so. Running a car on water is not exactly the most well known or widely accepted technique for saving gas. If it was as simple as pouring water into your gas tank, everyone would be doing it right? Firstly, it is not as simple as pouring water into your gas tank; rather it is the result of the interplay between the chemical makeup of water itself and the inherent inefficiency of the average internal combustion engine that makes saving gas by running your engine partially on the constituents of water possible.
So, before you can understand how this system saves you gas, you need to understand what the system is and how it works! The system which allows you to use water to supplement your fuel is essentially an on board electrolyzer that splits water into hydrogen and oxygen via electrolysis. After water is split into its constituent molecules, the hydrogen and oxygen gases are fed into the engine via the air intake. It is the remarkable effects on fuel burning properties within the cylinders which explains the increased fuel efficiency caused by utilizing this water for gas system, not the energy from the hydrogen or oxygen itself.
In other words, since you are using electricity from the alternator to split the water into hydrogen and gas, the laws of thermodynamics state that you cannot possibly get more energy out of a closed system than you put in. If there is a net loss of energy from the electrolysis of water, then how can running your car on water save you gas? The answer lies in the improved utilization of the gasoline itself.
But when a car runs on water, what happens in the engine? Normally, a gasoline or diesel engine does not efficiently utilize the energy within the fuel and much of it is lost in the form of heat, vibration, and even unburnt fuel. If you were to calculate the actual efficiency of the average vehicle engine, you would find it to be much less than 30%. This is due to the factors listed above. When you mix hydrogen with the fuel mix, the flame spread is improved as well as the efficiency of the burn itself. The extra fuel economy is caused by the ability of your vehicle to run on a leaner fuel mix than is possible without the addition of hydrogen. The increased economy afforded by the addition of hydrogen more than offsets the amount of energy lost during electrolysis, leading to a net gain in efficiency and gas savings.
