Another post about some other cool innovations I recall reading about, unfortunately there isn't much on the internet about these topics....
One pretty cool invention is Smokey Yunick's Hot Vapor Cycle engine, of which I could not find much information. I did find this article (
http://schou.dk/hvce/) which is poorly translated from German but still an interesting read.
Excerpt:
It should not work with any fuel injection it is very important with a caburator to hinna(?) prepare the mixture properly. he explains. Here happens the first heating says Smokey and points at a box below the caburator which omslutar(?) first part of the inlet pipe.
All water in the cooling system is forced through this box. All water is just 2 liter inclusive the radiator(?). There is no fan at all. Adiabatic... When the mixture has passed the box and is heated up to 90° Cit comes to the second step.
The homogenizer says Smokey and points at an exhaust turbin wheel which is connected to an inlet turbin wheel. Aha, like a turbo, yes? I nod to the cowboy hat so he will think that I can follow him. Smart guy and so on. No! Not turbo! he says a little offended. A homogenizer it should be. The purpose of the homogenizer is to fully atomized the fuel air mixture to an extreme fine vapor. Otherwise it would be impossible to futher heat up the mixture. When the mixture has passed the turbin wheel it is more heated. Partly because of the friction and partly because the homogenizer is incapsulated in the exhaust system. The mixture is now 140° C.
Next step is the inlet system which is totally incapsulated in the exhaust system. Here the mixture gets heated up to 230° C! Now things starts to happend.
Here it expands like hell Smokey explains and thinks that the fuel vapor expands a lot at this temperature. Exactly as we want to. Ofcourse. Here the homogenizer has a futher role: to be a back valve, to hold back the pressure which comes from the expanded fuel mixture. Without this back valve the top will be thrown to Orlando... well.. Besides the homogenizer presses with 0.45 kg. When the mixture reaches the combustion chamber more than 25% of the energy "is ready to go" (230° C). And with full compression, before ignition, the mixture has reached the extreme 820° C. After this comes the spark.
You see says Smokey, what forces the piston down is not the heat, it is the pressure... Because of the heat I hopefully reply (to win back some valuable points). Thats right says Smokey and put the glasses on his hat and go sit in his chair. The boots is naturly on the table. Thats about the story he says and light his pibe.
The engine has gotten a lot of flack for being black magic, or only working under limited conditions...but I think a lot of the doubts stem from the fact that Smokey didn't have an engineering degree of any kind, and just designed it off the seat of his pants. What was the "magic" that kept the engine from detonating with the superheated a/f mixture? Possibly trick ceramic coatings would be my guess, along with good head design.
Another related invention is a "Hot Fuel Injection" engine I read about in hot rod a while back. This is basically a direct injection engine, except it was designed by one guy in his garage rather than a team of engineers. He had fuel passages machined into the heads with injection orifices in the intake valve seat. The fuel would flow around the exhaust port before being injected, thus becoming superheated (and letting the heads run cooler). The superheated fuel atomized better and gave increased fuel economy, he reported high 30 mpg if I recall correctly (and had some independent tests to back it up). Then, he designed a new way to throttle the engine because now the amount of fuel was metered by valve lift. He designed a moving rocker arm pivot controlled by the throttle cable so that the rocker ratio was varied so as to increase lift as you throttle the engine up. If you are following, basically he thought of BMW's Valvetronic about 10 years before it was released to the public, and did it without any fancy electronics. It sounds like a whole lot to go wrong, but he had a 4.3 V6 with a large numbe of test miles and good drivability, and a static 454 V8 test engine.
There was also a company that was selling electronic-servo controlled variable ratio rockers with a similar design as a sort of VTEC system for old carbureted OHV engines. Can't recall the name though.
One problem with all these engines is they would never pass a sniffer test due to high NOx emissions, but they are cool ideas nonetheless. The HFI's designer published some statistics from a lab analyzing his exhaust emissions, and they looked pretty good compared to a regular gas engine, but thats only to my eye and I don't know what to look for.
