Originally posted by: CycloWizard
Originally posted by: BucsMAN3K
Lean Bearn Engines, however, adjust the Air:Fuel ratio (The higher the better) to bring more HCs to complete combustion, and according to this article adding hydrogen to the mix helps increase the complete combustion, resulting in more energy, and even better less polution.
It is generally true that you want to run the engine lean. However, there are other considerations that can compensate for running richer, as well as limits on how lean you can actually run and still get combustion or enough power to move. Generally, high temperatures result in NOx production. They also increase the amount of gasoline that is combusted and the fraction going to CO2 over COx. Thus, one needs to find some optimal temperature rather than just running high or low. If one lowers the fuel feed ratio (i.e. makes the feed more lean), then there is less fuel in the chamber, allowing lower temperatures to achieve the same conversion. However, if you make the mixture too lean, then the fuel will not combust at all. This occurs at the lower flammability limit (LFL) of the mixture. It's my gut feeling that the amount of fuel that needs to be burned to move the car will be higher than the LFL, which means one can't simply look up the LFL of the mixture and call it a day. This minimal mixture would pretty much have to be determined empirically, and would change with many factors, particularly throttle.
The problem with getting hydrogen gas is the amount of energy required for electrolysis. Your car battery just won't do it. But with these huge semi-trucks, they have enough energy to produce a bit of hydrogen gas to add to their lean burn engine....
They would have to tote around a lot of water to pull this off. The last hydrogen car I built weighed in at about two pounds and too about 15 mL of water to move it ~100 ft. Further, current fuel cells (e.g. Nafion-based PEMs) require highly purified water to avoid poisoning the membranes that perform the electrolytic separation and recombination. 1000 gallons of distilled water is pretty pricy, and distilled water also costs energy to produce. Thus, I doubt the net savings in fossil fuel consumption that this would yield in a global sense. The good news is that non-Nafion-based fuel cells may be coming up relatively soon.
Btw: That was in reference to the article about the trucks...as far as this guy's Ford POS escort or whatever it is, I don't have a clue. Exclusively on water? If this guy has can produce enough hydrogen through electrolysis with his 12V battery, I wan't to buy stock.
You can drive electrolysis with 12 V. IIRC, the electrolysis process is mainly current-driven, rather than voltage-driven. Car batteries can put out quite a bit of current and maintain a constant voltage. However, it will drain your battery pretty quickly. It will also have the drawback of having to store lots of distilled water. So it can be done, but the question is whether or not it's really a good idea. If your ignition system is up to the task, you could probably produce a decent amount of hydrogen using power straight from your alternator.
