Abstract: A hydroxy gas generator for an internal combustion engine is digitally controlled by a micro- controller and is installed in a vehicle. The invention senses vehicle RPM and uses a pulse width modulation signal of variable duty cycle with feedback to set the current to the electrolysis cell to one of three possible values. At zero RPM the current to the cell is zero. At an idle, a small amount of hydrogen is produced to aid in combustion but to prevent strain on the alternator. Above an idle, the system is running at full capacity to generate the maximum amount of hydrogen.