Very interesting indeed. Like a piston port 2 stroke. I would think it would be very dependent on exhaust pipe design to help scavenge out the exhaust gases. I bet it runs very smooth and can hit very high RPM's. Did I miss it or did they never speak of or compare Horsepower to regular engine?
That's pretty cool! It's kind of like crossing a Wankel and a CV Joint... I wonder if they'll pack the crank-case with grease for lubrication?
They touched on it, stating 14:1 on 91 octane with a very high revving design because of the "wave" pattern rotating mass. If I had to guess, it'll sound like a rotary engine on steroids. Whenever I see a "relatively" new designs I try to picture the wear items and the slop that ensues after 100-200k. I'd love to be a fly on the wall in their engineering teams layer, particularly the oiling systems discussions. If you think about the rotation and gravity of the oil being drawn to the "outside" of the rotating cylinders, how are they sufficiently cooling the inside cylinder surfaces? I'm thinking the oil pressure in the engine design has a significantly higher pressure requirement. I’d also like to see the reciprocator design, lubrication and bearing assembly. The load on the star has got to be massive.
the intake/exhaust port design is similar to a rotory. the problem is that the emissions are really hard to control. the port size really dictates the rpm efficiency of the engine. they do say that sense it can run a higher compression ratio it has reduced greenhouse emissions. that sounds like a cop out to me. i suspect the emissions on that motor are pretty bad. usually the simpler designs like the rotory and now the duke are harder to truely make more fuel efficient and emissions efficient. im sure they will figure out ways to help control the metering of the air fuel and intake and exhaust to make it cleaner and more efficient but they will be getting away from the initial concept of efficiency.
I think your likely right with the emissions angle, it's all really hard to say because Duke is really pioneering a new technology and all the facts have not really come out yet. They claim to be on GE’s short list but GE is really an activist company. I don’t but much faith or stock in them. http://www.dukeengines.com/news/duke-on-ge-ecomagination-shortlist/ Looking at their data sheet, the engine is producing torque but less power than a normal combustion engine as well. Also by reading the Power Density sections themselves it appears they may a max rpm problem. The data sheet states max rpm 6000 but they refer to their V3 engine at 3500 rpm. Maybe an anomaly in their writing or maybe they slipped. They also talk about variable compression ratio’s which to me seems to bolster’s your hypothesis about controlling emissions. I maybe wrong but I think that would add another level of complexity to their engine management control systems and to the states test equipment and or to their applications that control them (that’s a mouthful). I see major dollar signs in assimilating the engine into the main stream automotive industry. Much like electric vehicles today and their power station infrastructure yet to be built. http://www.dukeengines.com/advantages/power-density/
I see the weak point of this engine to be something like the Apex seal on the rotary engines. You figure you have the cylinders all rotating along with the piston in a circle how long before the seal between the chamber and the head fails. Unfortunately I can see mechanical wear happening in the sealing surface between the head and the cylinders and once that wears a little bit compression will no longer be held. Are you going to have to throw away or resurface the head ring, and what about the carrier for the cylinders is that going to be a one piece unit? I know if you change one of the cylinder liners out you will have to mill the whole deck to keep it flat. Then is things like carbon build up going to be a problem for this engine? It is easy to run an engine in a lab environment and constantly pull it apart and clean it checking components out, but what is going to happen when you put it in a crappy little car and let a 16 year old girl drive it, changing the oil once every 4 years and using as cheap of gas possible.
I hate to de-rail the conversation. But these guys REALLY screwed up on this one. For one, it should have been a six-cylinder, with the power stroke of an 8-cylinder. That way it could be "THE DUKE" engine! certified John way six-shooter action. They would CRUSH the American market with their six-shooter engine design.
