Hydrogen for fuel cells and IC engines.

[fay's unKle]

Some time ago I saw articles, most probably from car manufacturers, describing the ideas/wishes of some, to use hydrogen as fuel for their internal combustion engines, if the economies turn to it as energy source and thus satisfy the environmental requirements.

In my opinion it's not only the environment that has to be protected it's an economical matter too. Internal combustion engines can't get away of an overall efficiency in the low thirties while fuel cells climb to 80%. Huge difference.

We understand how admirably the engine manufacturers have perfected them during the past 100 years or so, but they have to do the same with fuel cells and a lot faster, because technology now is many times more advanced in all respects.It is my humble opinion that now fuel cells are not developed by the best and the progress is very slow, if I'm not mistaken there isn't a fuel cell ready for reliable use after almost two decades of research and development.

[EdEarl]

 

Some time ago I saw articles, most probably from car manufacturers, describing the ideas/wishes of some, to use hydrogen as fuel for their internal combustion engines

Please give a reference to this article, because I don't understand how it could work. Hydrogen fuel cells consume hydrogen gas and produce electricity. ICE burn petrol and produce mechanical energy. They don't seem to work together AFAIK.

[Bender]

It is possible to build an ICE that runs on hydrogen, but it will be bound by the Carnot limit and the efficiency will depend on the speed. Because of the higher temperatures, this also creates NOx, so the exhaust isn't pollutant free.

30% efficiency in an ICE only happens at optimal speed. In heavy traffic, it can go as low as 5%.

[Moreno]

 

Some time ago I saw articles, most probably from car manufacturers, describing the ideas/wishes of some, to use hydrogen as fuel for their internal combustion engines, if the economies turn to it as energy source and thus satisfy the environmental requirements.

In my opinion it's not only the environment that has to be protected it's an economical matter too. Internal combustion engines can't get away of an overall efficiency in the low thirties while fuel cells climb to 80%. Huge difference.

We understand how admirably the engine manufacturers have perfected them during the past 100 years or so, but they have to do the same with fuel cells and a lot faster, because technology now is many times more advanced in all respects.It is my humble opinion that now fuel cells are not developed by the best and the progress is very slow, if I'm not mistaken there isn't a fuel cell ready for reliable use after almost two decades of research and development.

 

There is no competitive ways to store/transport hydrogen. Gasoline energy density = 34 MJ/L. Hydrogen (compressed at 700 bar) = 9 MJ/L. Hydrogen liquid = 8.4 MJ/L.

https://en.wikipedia.org/wiki/Energy_density

 

Fuel cells have many fundamental problems difficult to overcome. PEM fuel cells efficiency = 45-50%. Close to 40% for a system.

Alkaline fuel cells claimed to reach 70%, but much larger in size than PEMs and are quickly poisoned. Still they may be used in some London's taxies.

http://www.parliament.uk/edm/1997-98/1597

 

Heat engine efficiency depends on heat sink temperature. Modern ICE are still far from a limits possible.