I didn't know where to put this so I put it here.

 

Why are car companys making hydrogen fuel cells, why don't they just make a hydrogen internal combustion engine I know it can be done, but there must be something I don't understand because they seem to all want to make fuel cells and not internal combustion engines.

 

Could someone please explain and educate me as to why hydrogen fuel cells are better than hydrogen internal combustion engines?

Fuel cells are much more efficient then internal combustion engines.

To expand on Johns answer, Hydrogen is expensive (or rather, it would quickly become expensive once it becomes a major fuel for transportation until more production plants are created). Therefore there is a strong incentive to use the hydrogen as efficiently as possible. ICE's have a hard limit on efficiency of about 30% thermal. they will never get better than this because of thermodynamics.

 

fuel cells can reach up to 85% efficiency but a more reasonable value for one used for transportation is about 50% This is still far and away better than an ICE will ever be.