Well I've tried a version of this idea before, but I've made some edits and I think I'll try again.

So wankel engines are incredibly good at making high power at high RPM. The only things they lack are torque and decent fuel economy. Well there is already a version of the wankel engine that uses steam, so why not combine the two and subtract a couple problems? My idea is relatively simple. It is to use a supercharger to scavenge the chamber of its exhaust and fill it up with new air, all in one chamber. This frees up the 3rd chamber for steam power. Now the thing is that the exhaust would have to be tuned to have basically no backpressure, otherwise the supercharger would have to work too hard and the steam power wouldn't make up for the supercharger's losses. However, if the exhaust is tuned for barely any backpressure (perhaps some kind of ram air exhaust?). The engine would be direct injected, and therefore wouldn't produce anywhere near the amount of hydrocarbon emmisions that most wankels do. The water injection (steam stroke as I call it) would be the engine's only cooling source, and I reckon it would make enough power during the steam stroke to allow the gasoline injection to be lean enough so that it wouldn't require a cat. (the european Audi A3 with direct injection doesn't need one). Now I don't have any good numbers to do any calculations, but I figure that the supercharger would rob 20HP at most, and the steam power stroke has to produce at least 60HP+ at its peak (not to mention a nice amount of torque). I figure a 40HP+ gain without the complications of a cooling system is a good gain.
-- acurafan07, Jun 28 2007

Steam Wankel http://ghlin2.green...apatter/wankel.html
Seems interesting [acurafan07, Jun 28 2007]

Bun.

Having two power strokes happening simultaneously in the same chamber just sets me all atwitter.

Does the Wankel use axial ports, i.e. the intake and exhaust openings are in the end caps, and not in the periphery?

I've always wondered if there was anything that acted to cool the rotor besides the intake charge. This would do that nicely.

Again, if there's plenty of expansion left in the steam after the steam stroke, you could tap that to run the scavenger.
-- elhigh, Jun 28 2007


Thanks for the bun. Using the leftover steam expansion to run the scavenger would be excellent, I just don't know how that would be possible. Since there would be no leftover space, the steam and gasoline exhaust would have to exit the same chamber (Btw, you do know that I'm talking about the steam expansion happening in the chamber after combustion, not during, right?).
-- acurafan07, Jun 28 2007


Combustion on one side of the "8," steam on the other side.

However, the traditional Wankel shape may not work. I think you'd have to have a four-lobed rotor inside a three-lobed chamber to make it work. Apex seal lean angles become pretty extreme in that design.

Makes me wonder: what would water injection do for the StarRotor engine?
-- elhigh, Jun 29 2007


//Apex seal lean angles become pretty extreme in that design.// You can say that again. Scares the pants off me.
-- MaxwellBuchanan, Jun 29 2007



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