water engine

Anyone ever heard of someone fueling their car with water via some sort of 'reactor' which turns the water into hydrogen and oxygen vapours?

I'd seen a video tape which purports to show a couple of oveseas (non-USA) drivers who'd done this but I've no knowledge of anyone here.

It seemed simple enough - 2 metal plates suspended in vessel filled with water, having a vented tube to the carburator intake and a fill tube. They attached the plates to the battery (intermittantly) to make the water start to foam.

Anyone here tried this? What happened?

I've seen water injection where the car is running off gas & water is metred in as a performance aid. If someone ever figures how to run a car off water alone they'd be famous, as splitting water into hydrogen & oxygen takes more energy than you get by burning the hydrogen & we haven't mastered fusion reactors.