There is a system that allows you to reduce the fuel consumption in your car at a very low cost. Simply use your normal fuel mixed with the hydrogen generated in your own car in a process called electrolysis - the splitting of water (H2O) into its gaseous component parts, hydrogen (H2) and oxygen (O). These gases are directed toward the engines combustion chamber, via the air intake manifold, where they mix with carbon based fuel (Petrol, Diesel, LPG, CNG) and there they are ignited.
This increase the octane level of the air/fuel mixture and allow the fuel to burn almost completely, thus reducing the amount of pollutants realeased in the exhaust. More informations you´ll find on Wikipedia here: Oxy-hydrogen and Browns-gas It´s a simple technology that you will be able to install in your car without the help of a mechanic