Mel Tisdale
For a more detailed analysis of this engine it is worth following the link in the opening line to the earlier (2012) Gizmag article. The comments are also very informative. For the record, I think those of Pikeman and Sleat just about nail it.
I suppose there must be some credibility to the design seeing as it clearly has not disappeared into vapourware heaven - yet.
Josh Coray
Very interested in this motor, it is a good application for a small concept we were looking at.
Might have to pick one up.
A compress to ignition in a homogeneous fuel air mixture using a high octane fuel offers the same advantages without having to totally retool the factories. or salve the seal problems.
Hovnimrsk Prdelac
@ Mel Tsdale - the main complaints of Sleat at the previous article was a missing animation or detailed picture of the engine in work. That's no more the case - very clear videos are now available in Youtube and I wonder why they were not presented in the article, because they are indeed quite interesting. For example this one:
Very interesting. I wonder, why are not such small yet efficient motors used for Hybrid applications.. Or, as article suggests, lawnmowers, home electro-power generators, etc. Thousands of uses!!
@Hovnimrsk Prdelac - quite fascinating nick
so it is a modified Wankel engine? while Wankel has 2 pockets for combustion, this has 3 and a different design for the center part.
Very interesting design, but it still retains several compromises that may prove fatal to the concept: 1/ The rotor has an enormous circumference and travels at 2/3 crankshaft speed. That means that the seals will have to function at stratospheric pressure velocities. 2/ The combustion chamber shape is awful. 3/ Some of the expansion forces are working on the wrong side of the crankshaft. 4/ The rotor is being heated from both sides. The result will certainly be poor specific fuel consumption, eye-blistering emissions and marginal service life at peak rpm and output. Perfect for low-cost and disposable ISIS attack-drones though.
But just how efficient is this engine, i e, what is its thermal efficiency ? The larger X2 was reported to boast an efficiency of 75 % ; is that the case also for this scaled-down version ?...
So lets see if I have this right. This company has been in operation for 11 years and has managed to produce two test engines. This particular engine currently has a TBO of 3 hours and BSFC of 545 g/kW*hr -- (15% efficiency). They *claim* that they will get to TBO 1000hrs and 30% effeciency .. but I can't find any evidence that either of them has designed or built a production engine before. Meanwhile small, light, mass produced strato-combustion engines can do 400g/kW*hr all day long -- with greatly reduced emissions relative to old-school ported 2-strokes.. Hrmmm looks like more Ph-Ds running a professional grant-hunting business.
This is amazing, in my working live I worked a lot with liquid ring compressors, sometimes called liquid piston compressors. Never did I think that one could turn that principle around to change it from a driven machine to a driving machine. Well, that's life.