Attempt to explain what is happening:
Let’s see if I can p!$$ everyone off:
Yes, there is a little ‘snake oil’ to HHO generators, but there is also a little truth. I don’t know how much an unmodified engine can benefit, but there are improvements.
So, let’s start at 1st principles – what are we trying to do?
We are trying to push a piston down a cylinder. The simplest is to use compressed air (large diesels are started this way). But compressed air is really lousy medium for storing energy. One step better is storing energy as liquid, and converting the liquid to gas and expanding the gas (CO2 cartridge works this way). But still not very good because the state change from liquid to gas and the expansion of the gas resulting in cooling of the medium which reduces the effect.
So, better solution is execute an exothermic chemical reaction (one that gives off heat, i.e. burning). E.g. 2 H2 + 1 O2 => 2 H20 or 1 C2H5OH (ethanol) + 3 O2 => 2 C02 + 3 H20 or 1 C8H18 +17 O2 => 8 C02 + 9 H20. The exothermic reaction heats the air up from e.g. 500°R to 2500°R (we must work from absolute zero, so use Rankin, not Fahrenheit, 500°R = 40°F)
The other engineering equation in play is PV= nRT, (P is Pressure; V is volume of our cylinder; n is of moles of gas in the cylinder; R is ideal gas constant and T is temperature). So, as we are only changing P, V and T; and have increased the temperature 5X, the Pressure increases 5X, causing the piston to scoot down, increasing Volume, driving the rear wheels.
Our chemical engineering friends take our formula for burning Octane (C8H18) and convert it to weighs. And come back with that ideal mixture (stoichiometric) being 14.7 lbs of air to 1lb of gasoline.
But the hot-rodding redneck comes back and says, while 14.7:1 might be the ideal, his engine makes most power when run at 12:1. Because this is the real world, 80% of air is Nitrogen. And Nitrogen doesn’t just not make a nice exothermic reaction, it also prevents some of the Oxygen and Gasoline molecules from getting it on. So, we add a little extra gasoline to use up as much oxygen as we can. Now, this has some bad side effects, the unburned fuel comes out of the exhaust as smog. (There’s more to smog than just unburned fuel, but I'm simplifying a bit), but it makes for best power. The extra fuel also cools the mixture as there also material limitations to how hot we can make things.
So, manufacturers limit the ability to run rich, and add catalytic converters to ensure all the fuel is burned.
Where is this boring engineer going with this mansplainin
This is where our “snake oil” comes in: Having some additional H2 molecules in the mixture allows for more thorough combustion. If you burn 95% of the gasoline rather than just 90%, there will be an improvement. Then add in a bit for the actual HHO that you are burning and you can reduce the throttle opening and you are getting better fuel economy.
Add in that you are thinking about fuel economy and doing some of the “hyper mileage” tricks, and you see a significant improvement.
Note: One of the items which is very hard to measure – how much are you drawing down the battery? If your alternator isn’t keeping up with the discharge caused by the HHO generator, it might not be noticeable in an hour drive. But when you come out and your truck won’t start, you will know where the extra energy came from.
Now, you can do some other tricks that are probably better for increasing the efficiency of your engine – Increase the compression ratio (say 13:1 or more) and then use water injection/throttle manipulation to control detonation.
I played around with propane and water injection on the diesel tractor back home. Good for increased power without the “rolling coal” that tipped Dad off that you were experimenting with the family’s means of producing a living.
I didn’t have the facilities/equipment to try Bruce Crower’s 6 cycle engine (Intake, compression, power, exhaust, water injection, steam exhaust). The idea being you injected water into the hot cylinders and took advantage of the boiling to both extract power and cool the engine (little or no cooling radiator, slow down the water pump).
Tractors have the advantage of a constant speed/load and extra weight isn’t a drawback (we were adding liquid to the tires/suitcase weights anyways).
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