Interesting read, however it looks to me like it was written by a know-it-all 2nd year chem student rather than a fuel chemist and someone with extensive knowledge of internal combustion engines.
Here’s one quote that caught my eye:
But, but, but… the claims are that the hydrogen is a “catalyst” and makes the gasoline burn more efficiently.
So? That claim is just wrong. We know we can’t affect the thermal efficiency of the Carnot cycle by very much, so 75% is still going to be “wasted”. Even if the hydrogen did act as a “catalyst”, there is no more energy to be released—99% of the gasoline does undergo combustion. A 300% gain in efficiency would imply that we are now getting 399% of the theoretically-retrievable energy that the gasoline contains (well, actually more than 399% because we also need to cover the losses from the electrolysis). This is just asinine and Carnot says otherwise. Energy can not be created from nothing—the gasoline can NOT give more than 100% of what it has.
An internal combustion engine runs by generating a certain amount of pressure in the chamber for a certain period of time. Simple chemistry equations cannot model the peak pressure and average pressure inside a combustion chamber at different RPMs , cylinder filling, spark timings, etc.
Let’s assume that 99% of the fuel does in fact burn. That doesn’t mean it burned efficiently to create work. It doesn’t take into account how fast it burned and when it burned in the combustion stroke. Speed of burn and burn timing are two important factors to translate pressure into engine work. Any fuel additive (hydrogen or otherwise) that allows a higher compression ratio, better spark timing, and/or higher average chamber pressures on the down stroke would have a higher efficiency increase than the authors simple equations would predict.
Engines can be made to run lean at idle and at light cruise speeds. EPA requirements limit the emissions though and most manufacturers don’t seem too interested in making engines that can run in leaner conditions while still passing emission testing. That requires new catalytic designs, new head designs, etc.
The hydrogen hype may be BS on this scale but that author doesn’t know enough to convince me.
This thread and my latest gas fill-up got me interested in doing research and I just stumbled across these videos:
http://www.youtube.com/watch?v=hFifFR-4C28&feature=related
In video 3 in the series he explains how the super fast burn speed of hydrogen can allow the engine timing to be retarded and still burn the gasoline while the crank angle is still ‘right’. It would be acting as a catalyst in that case. It makes sense and matches what I know.
BTW, I only watched the first 3 videos and don’t know a thing about that guy. If he goes batshiat insane later on in the series please don’t blame me