Full expansion cycle engine

[Tony Patman]

This thread is sparked from some confusion which arose in this other thread concerning whether a Wankel engine is a rotary engine. Anyway, during the discussion, Richard Bond referred to a cunning, novel design for a full expansion cycle engine. I've never seen anything like this before, and I thought it warranted a thread to see if anyone's got one, seen one, tried it, wants to. Maybe this is all common knowledge amongst the cognoscenti on here, but I'm fascinated anyway.

The diagrams and animation indicate that this is not a Wankel, although the outward appearance of the crankcase does make it look rather like one. It's claim to fame is that it is the "first practical full expansion engine. True full expansion is achieved when gas expansion continues inside the mechanism to a final volume 3.5 times the original swept intake volume. This allows the gases inside the engine to reach atmospheric pressure. The full expansion process uses all the available energy to produce work. This results in a cool exhaust without any exhaust blow down noise."

So how does it do it? Well, it has combustion chambers for both high and low pressure, with the initial bang taking place in the primary chamber and then being ported to the secondary one for further expansion all the way down to atmospheric pressure. That much is not new in principle; well, maybe as applied to glow engines it is, but the idea's been used in steam engines for a very long time, with high and low pressure cylinders. The bit I find mechanically fascinating with this engine is that the primary chamber is inside the piston of the secondary chamber, reciprocating perpendicular to it. Thus there are four chambers in use. I suppose if you designed a conventional engine equivalent, it would have four cylinders, two high pressure and two low pressure; but this design cunningly wraps all that up in one chamber.

Crikey. Sounds like fun. Wish I had £225 or so to blow on one. Better start saving up.

[Tony Patman]

OK so I'm the only one who finds this interesting

[Myron Beaumont]

Tony .Oh no you're not .I think it's all down to the dreaded manufacturing costs/reliability/economical value/ Bla Bla Bla    How green it is etc .?  I put out a thread to relate to possibly our model engines ___offered details available -for free  (having payed for them) Guess what?- All I got back was basically ridicule . You can't win all the time -if ever !  Read the one on water power and associated threads- you'll know what I mean ! But before pre- judging me ,read the info available first -Not a lot of folks do that ! AS in your case  if you see what I mean Sincerely Myron

[Myron Beaumont]

PS Tony .I am a mechanical engineer  RR trained not some "fitter"

[Tony Patman]

You're right, Myron: people tend to pile in with their pre-conceived ideas and flimsy assumptions before they've read up properly.  When you say "our" model engines, do you mean the RC modelling fraternity or some company or organisation with with you are involved?  Water power sounds intriguing, but I thought water couldn't be compressed? 

Wish I was a mechanical engineer, not just another desk-jockey...

[Myron Beaumont]

Tony   just tried to send a comprehensive reply & all of a sudden it disappeared .Will try again when my anger over this M/C has subsided. Myron

[Allan Jordan]

 Hi Myron, I must admit to finding the concept of water power fascinating, I/m sure I don/t have to tell you

 to disregard those  who regard water power as a joke. Love to see their faces if can be viable though !

 When your anger subsides please tell me more via e-mail .  Regards Allan.

[Myron Beaumont]

Tony & Allan   Its nothing to do with compressing water at all! Read my threads & spin offs There are several pointers to the facts & I can't actually remember what I've written ( I have a small lap top with problems as well) Try "Water4 Gas "and do what I did and follow the threads that are available. As Ive said before on another thread the brother I've never met yet but just discovered is a millionaire in Florida & his "handle " is the H2O guru  In other words he knows a bit about HHO--- NOT particularly Water H2O as we all know it .As I've said I can forward the info available free & legally 'cos the patent that the oil companies bought ran out recently . PS  there is more than one way of  utilising water( a package of energy ) than the oil people think they can convince us of .Any way Please read the facts ---If you're seriously interested & no I have no commercial interest whatsoever other than that of our planet . & the value of that is beyond any money .There has to be an answer (not oil for evermore ) read & learn .Cor Blimey .I sound like one of those evangelists don't I ?.I just thought .Wouldnt it be nice if aeromodellers set the way for future power systems in their own way

[FlyinBrian]

A very interesting concept, ( the full expansion cycle engine) I'd love to see one run.

[Tony Patman]

Crikey, Myron, you're a real evangelist for this.  It does sound very interesting, and I will definitely look through the information you've made available.  Anything with a decent power-to-weight ratio is worth considering, and if it is a clean technology, all the better.  I doubt the CO2 from glow-fuel model engines is significant next to that from cars, trucks, power generation, shipping, aviation and industry in general, but I do agree with you that the modelling fraternity is well-placed to explore and develop new energy technologies.

[Tony Patman]

Myron, I think I've found the right thread, and I can see where you refer to an "attached" document, and I think I need to email you for it, so I will do that now!

[Erfolg]

I have looked at the site and do not realy follow thecombustion process. Yet feel what is missing is a description and analysis of the thermodynamic cycle. As many will know there are many cycles, Sterling,  Carnot, Ideal, Otto etc., which are used to analyis the effiencies of heat engines. Some appear to produce very high efficiencies, ie the Sterling cycle. In practice these efficiencies are not achieved for a variety of reasons. In the sterling engine it is the heat recovery component. Yet the analysis gives an idea of the potential.

Some engines such as the Wankel have been attractive due to the physical charaeristics, ie low component count, small volume etc.

However a trip through the science museum tends to emphasis that complex engines very rarely if ever achieve commercial sucess, Perhaps the gains in effiecencies are never achieved, the maintenance is to high, or the engine to complex to prodece, just could not be made to run properly. I think the Woolmer motor cycle engine was of this type.

The science museum has more engine types than you can shake a stick at. Yet there are very few that make it, Simple expansion Steam Engine, Steam Turbine, Gas Turbine, 4 stroke IC etc ar amongst the few.

In short very interesting, but what is unique and has it been quantified and demonstrated.

Erfolg