Friday, October 28, 2005

Have Israeli engineers invented a car that makes its own fuel?

This article from an Israeli news sources, and republished on the ghastly Free Republic site, says that an Israeli firm solved "all obstacles" regarding emission-free hydrogen engines.

I detect the odor of fish. But I'd like to hear a response from someone who better understands the science.

5 comments:

Anonymous said...

What obstacles? A buddy of mine, in his own shop, converted his car to a hybrid that could run either on gas or hydrogen by flicking a single switch. He produced the hydrogen by solar/wind power. All fuel cell driven hydrogen engines are, as far as I know, emission-free.

Anonymous said...

I'm not an engineer, but the article sounds like BS. IMHO.

Milo Johnson said...

Hydrogen, because it is such a tiny molecule, has a very low specific impulse (the "push per pound" in a sense,) and to generate enough motive power for a full-sized car a hydrogen BURNING engine would have to be of incredibly high efficiency while still burning a lot of hydrogen fuel, and would require an extremely large tank to hold enough hydrogen to be able to drive any distance. Hydrogen fuel cells provide motive power indirectly by generating electricity, and once again, you would have to have a lot of them in one vehicle to be able to use hydrogen as the exclusive power source. The problem is similar to the problem with solar-powered vehicles. The amount of energy you get isn't adequate to the task of moving a vehicle of any size with any real acceleration. You may as well try to build a windmill-powered car.

Smells like mackerel to me...

Anonymous said...

Um, where is the energy coming from in this little contraption? They say the water is being heated - what is producing the heat?!?!

Always keep the first law of thermodynamics (conservation of energy) in mind when assessing stuff like this.

Anonymous said...

Nevermind my previous comment. Looking at it more carefully I see that the water is heated by the reaction of the metals with water.

Okay, this idea could work in theory but I'm skeptical that it would be efficient enough for it to be implemented in practice. The three main problems I see:

1) How many miles per kg of metal can you get? This wouldn't be hard to calculate but I'm too lazy to do it right now.

2) How efficient is the process for recovering the metal from the metal oxide produced by this process? This is where the energy is coming from.

3) You would need to set up a whole system for collecting the metal oxide and transporting it to the power plant or whatever is electrolyzing it back into the metal fuel. That could be done but the transportation costs would be high.