Quote:
Originally Posted by freebeard
drrbc -- cross-post. I just wanted to post that old cartoon and mock it; where it goes from there is open (nanomachines?) but hopefully steam related.
I'll check the article.
Edit:
What do you think? He uses an equation that he doesn't give, and suggests the Vs (I assume velocity?) drops from 1700 to 1440fps. Which suggests a smaller volume over time, but steam is going to expand the volume. 
I can see reducing radiant heat off the pipes to keep velocity up, that's why thermal wraps. This maybe uses heat of vaporization to reduce the energy in the gas so it doesn't heat up the pipe it's passing through, instead.
I don't know why it would be limited to two-strokes; but what's the advantage over injecting the water into the combustion chamber? |
Well hell, I wasn't actually planning on re-reading the damned article- I was just pretending this was important so that sadistic physical therapist would quit trying to rip my arm off for a second.
But yeah, that sounds right. Despite the 1700X volume increase for turning water into steam the temp at 9,000 rpm went from @ 700ēK down to 425ēK, so I'm guessing you could assume a lower speed of sound. From that calculate the distance from the port needed to have the rarefaction part of the exhaust pulse wave "pull" the exhaust gas out.
So just off the top of my head, I can see some improvement in a 4 stroke gasser, just less than a two stroke. As in the two stroke the intake charge is being pulled into the cylinder as the exhaust is being pulled out. Not so in a 4 stroke. So I'd expect 50% less power improvement per cycle, but I also suppose I could live with 12% more midrange HP or torque. Could be better in a diesel though.
As far as just injecting into the cylinder that sounds a bit complex for the DIY'er. My uncle said it worked great on those 2,200 hp aircraft engines when they'd double the boost from the supercharger. He said they were able to get the hp from @2200 up to 2800 which would allow them to get an overloaded aircraft off the ground in the hot thin air.
But it sounds like to tune the exhaust all you really need is a measuring tape and a drill. (Well, maybe a valve. And a rpm sensor. A water reservoir. A pump too. OK, maybe a bit more than just a drill and a tape measure- but you get my drift.) It should be doable by someone mechanically inclined (not me certainly!).
Anyway, it was just a thought.