Hydrogen HHO generators use electricity from the battery of a vehicle to split water (H2O) into Hydrogen and Oxygen. Hydrogen is generated only when the engine of the vehicle is activated and it is never stored in the system. The instant that HHO is produced, it gets immediately injected into the engine where it blends with the existing fuel. The resulting mixture burns more efficiently, reducing fuel consumption and the amount of pollutants released in the air.
Pininfarina H2 Speed Concept -- hydrogen fuel cell technology, produces around 500 hp from two electric motors, with a direct transmission, carbon chassis, dual wishbone suspension, and carbon brakes helping performance along. 0-62 mph in 3.4 seconds yet produces no emissions