Cyclone Power is developing the Mark V engine and claiming it can run on "almost any fuel." In actuality it looks a little like a lawnmower engine in size. In principle it runs off a rankine cycle or regenerative heat cycle or, they claim, a Schoell Cycle named after the inventor who originally developed the cyclone engine. Rankine follows a four step process:
- 1 ->2 Fluid in liquid stage pumped to high pressure
- 2 ->3 Heated at constant pressure, becomes a saturated vapor
- 3 ->4 Vapor goes through a turbine, generates power
- 4 ->1 Vapor enters a condenser and becomes a saturated liquid
I'm a bit skeptical as to their claim of this being anything "new" or being able to run on "any fuel." I talked a bit on Engineer Blogs about diesel and the way a compression ignition engine versus a spark ignition engine functions are pretty different. Just because their engine might have some flexibility does not mean it wouldn't lose a lot of its efficiency depending on what the working fluid is. They're claiming they can use algae or waste oil as fuel but honestly this is nothing new. Most diesel engines can be easily (or fairly easily given you have time and know what you're doing and have a little money for parts) modified to run on many other kinds of fuel. That's the whole point of biofuel, it runs in engines we've already designed and are using. Especially in large vehicles and trucks which still account for a huge percentage of our transportation costs for shipping product in this country.
Getting all that aside, I do think it's interesting. You don't see a whole lot of radial engines these days. Combining it with a rankine-type cycle and focusing on growing demand for biofuel power generation devices is probably pretty prescient. But there's reasons we don't use external combustion engines in our cars or airplanes so we need to keep looking for practical solutions for that fit our society for both cost and environmental reasons. And maybe something like this can be a part of it.
I think hydrogen engines are promising (maybe that's a whole future post?) and while small, solar powered stations might work for individual's cars it won't serve as a substitute for the whole power structure. Clearly we need diversity in our power solutions and maybe this clever little engine can be a part of that.