The HHO dry cell contains a stack of metal plates (with every other one connected to a positive or negative battery source) submerged in water. As electricity tries to bridge the small gap between those plates, it must pass through the water and break its molecules, producing HHO. The HHO passes through a tube connected to the engine intake, where it's siphoned off by engine vacuum. How Does HHO Work on My Car? It's very simple. Our HHO Dry Cell uses 12 volts of electricity from the engine and produces HHO gas (hydrogen + oxygen). You won't change or modify your engine. On newer cars with electronic fuel injection, the ECU (car computer) will have to be tuned as part of the HHO installation. The technology is simple, effective and safe.