Very interesting. When I was at Symbolics back in Cambridge MA in the 80's there was this MIT guy from across the street working on an electrical engine where you had big edge-wound voice coils around the cylinders (much like high power pro speakers). He absolutely believed and talked about regenerative braking etc. Never heard where that ended up but he was fun to talk to. Sent via BlackBerry by AT&T -----Original Message----- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> Date: Tue, 8 Jun 2010 19:01:48 To: opendtv@xxxxxxxxxxxxx<opendtv@xxxxxxxxxxxxx> Subject: [opendtv] Off topic: Iris engine This new idea for an internal combustion engine is interesting, but the explanation is basically wrong. http://www.irisengine.com/6901/index.html Think of a piston engine, where not the piston, but rather the cylinder walls, move out with each spark ignition. Would it NECESSARILY be more effcient than having the piston move and not the cylinder walls, like a standard puiston engine? In theory, no. In practice, *probably* yes, because the greater area expanding out will keep most of the engine's internal surface area cooler (gas cools as it expands). So you don't need as powerful a cooling system to keep the metal from deforming, which creates less waste heat. But other practical considerations also exist. The expanding walls are called "chordons." The chordons have to create as gas-tight a combustion chamber as possible. With piston engines, you just stack up rings until you're satisfied that only small amounts of gases blow by. How about these "chordons? Looks like a narrow surface that does the rubbing, sort of like a Wankel. I'm dubious about the huge gains compared with piston engines. Also, check out all those crank shafts you need. One for each chordon. That can't be good either, in terms of friction losses. Their explanation only addresses the "working area" of the engine. They state, "Surfaces exposed to combusting gases in an engine can react either productively, by moving, or wastefully, by heating." I don't buy that explanation. If a surface heats, but that heat is allowed to stay put, you don't waste anything. So what they really mean is, a piston engine would need to be made of more expensive materials to equal the efficiency of this Iris engine. Could be. And the counter argument is, let's not forget to obsess over the sealing surfaces and parasitic losses! Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.