Quote:
Originally Posted by TeeSter
I'm no expert on ICE's but you'd think the heat released would keep the water in vapor form until she makes it to the exaust wouldn't it? I mean all "fuels" produce significant water vapor when burned don't they? . . .
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The problem is the intermittent combustion. The first 'firing' provides some heat but the cylinder head and spark plugs are going to mostly be at ambient temperatures until enough occur to transfer heat below the surface. During this time, especially after the exhaust valve opens and the pressure and temperature plummet, that condensation and even ice can form:
http://www.sacskyranch.com/eng182.htm
Now has the ratio of carbon to hydrogen goes up, the resulting C0(2) and CO tends to dilute but not eliminate the risk. But burning pure H(2) sounds like an invitation to more spark plug icing.
As for using H(2) as a fuel, extreme rockets, maybe, but liquid CH(4) has excellent characteristics and compared to liquid H(2), a much better solution. Perfect is the enemy of 'good enough' and in this case, CH(4) makes a lot of sense.
A little known fact is the X-15 rocket plane used NH(3), that boils at -33C versus -161C of methane. I've long thought ammonia would be a better hydrogen transport mechanism than methane for a fuel cell because it decomposes into a very pure H(2) and N(2). Due to the formation of nitrogen oxides, ammonia is a poor engine fuel.
Bob Wilson