If distilled water is not used in a direct injection water system you will get mineral deposits buildup in the engine and exhaust. That can't be good. It'd be just as bad, if not worse than carbon buildup.
Even if you had to use distilled water if you are able to reclaim and reuse it then it would not be much of an issue or problem.
Something like a 3 gallon system that is constantly filtering, injecting and reclaiming it. Then it would seem it only needs to be topped off weekly and changed maybe monthly?
This concept seems to have a lot of potentail and few drawbacks. Nothing that some of our brilliant minds could not find solutions for.
The gas savings really could be huge and I think it needs to be looked into. This may work better on a Diesel type motor, one cycle diesel fuel, one cycle water. The higher compression and slower piston speed may make it more compatable with diesels. Curly
How can you reclaim it? It would be leaving the tailpipe as steam. Even if you tried to distill the exhaust (not practical) you'd end up with more than just water. You'll probably end up with acids in there as well. (You know, like acid rain)
That's where the 3 valve system works. Not just 3 valves, but 3 different ports as well.
1 intake, 2 exhaust.
One exhaust valve opens on the "fire" exhaust stroke, and vents out the tailpipe.
The other exhaust valve opens on the steam exhaust stroke, and with a second set of exhaust pipes, routs to a condenser in place of the radiator (probably through a filter before that), then to the water storage, replacing the coolant overflow, and then through a pump, another filter, and injected into the engine again.