Just my 2 cents but, everyone is right making the hydrogen will cost more power than you gain... But when it mixes with the diesel it will ignite better and burn more efficiently! thus fixing that problem and giving you better performance. The deuce is not computer controlled so It will not make the computer give it more fuel so you wont lose gas mileage only gain it. Not to mention with the rpm and the mass of that motor turning at 2000 rpm its not going to notice the increase in draw from the alt...
Why would adding pure hydrogen to a hydrocarbon make it burn "more efficiently?"
What do you mean it won't notice the increase in draw from the alternator? Of course it will. The fact that the the engine is capable of providing the power necessary to crack the water has nothing to do with it.
TANSTAAFL. There ain't no such thing as a free lunch. Alternators don't turn of their own free will. The more load you put on them, the harder they are to turn and the more energy they take to turn.
I have an experiment that will PROVE to anyone beyond any doubt that this is so:
Take a stationary bike generator and pedal it without it being hooked up to anything. Pretty easy, right? Now hook the leads up to a battery and try to charge the battery up. Ugh, it's like riding up a mountainside!
But wait, we just disproved a fundamental law of thermodynamics, didn't we? We're charging the battery for nothing! Free energy, right? Wrong.
You're burning more chemical energy stored in your body to turn that generator with a load on it than you would be to turn the one without anything connected to it.
Oh yeah, and the kicker... guess what? Even when you were pedaling the bike without the battery hooked up, you were still burning energy. Why? Friction. Friction in your muscles, in your joints, between your feet and the pedals, in the bearings of the wheels... everywhere.
This is why if you were to implement one of these HHO schemes on a large enough scale to make any kind of noticeable difference, the difference you're most likely to see in fuel mileage is a significant decrease.