You can install these on a petrol vehicle.

Use distilled water, and 316 stainless as consumable electrodes (most other materials are consumed too quickly, and the water gets nasty and contaminated.

Feed the 2H2 and 02 into the air intake after the air filter (IIRC).

I've seen it on an old Bronco II. Boosted the fuel economy from 11-12 mpg to 15-17 mpg, and the motor stopped knocking.

My buddy was pulled over with it, and the contraption was doing on his passenger seat (wires and tubes).

The officer was initially suspicious, but there's no law against it (in my area).

It's already patented and shelved, so you'll get in trouble for selling them.