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I still see that Revetec has the dubious claim of being the "World's most efficient petrol engine" on the website.
How about Fiat's new Twin Air engine?
Quite an interesting engine. Only 900cc yet it can put out 85HP and a whopping 145NM at 1900RPM (which is what the 2.4L revetec could manage).
I wonder if Revetec would do the ethical, moral thing and change their label...
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talking of being ethical and moral :(
First, check out websites and you find it happens. At the time of writing true and CAN be legitimately left that way. Not ideal. But that's the internet for you :)
Next, rather than your BS in the latter part, why not be POSITIVE and engage in REAL discussion rather than challenging. After all they may have forgotten that was posted and woudl appreciate a reminder. Just try doing it in a better way than that above :(
As it is the post is drifting away from the techincal and we KEEP reminding that this isn't the forum for moaning and complaining. Take that aspect elsewhere or I'm in mood for a ban :) ( wont but DAMN I want to :) )
PS: you might want to fix the sig too. Power has NOTHING to do with the wall. That is inertia/momentum/mass and NOTHING to do with power. Just as accelreation has nought ott --- Traction and FORCE -- ie torque :) :) Just ins't a great reflection at the moment on your knowledge.
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Taking it a little harder then needed I think Matra...
A quick few points before I continue with a technical aspect discussion topic:
The Revetec was NEVER the most efficient petrol engine in the world... The best I can find is mention that it achieved the highest peak efficiency measured by Orbital
The words: "The World's Most Efficient Petrol Engine" are on the main page in a massive banner... They wouldn't have "missed" it or forgotten.
I brought up the TwinAir engine to actually lead INTO a technical discussion...
Finally as to your critique of my sig: It has all been covered in many other threads... Glad you got rid of your own formerly obtuse sig. and replaced it with one I quite like :)
On to the technical discussion that I was leading into...
The TwinAir engine is wholly designed to take maximum advantage of the MultiAir valve system. However the MultiAir system is wholly top-end technology and therefore there exists the possibility of marrying MultiAir with a revetec bottom-end.
Obviously the point would be to create an engine with even higher efficiency, however this brings a key point forward.
Do we actually have any proof that the revetec bottom-end is any more efficient than a classical design?
What sort of testing should be performed to achieve a definitive answer to this, most important, of questions?
I agree that the revetec offers several interesting aspects that can be tailored in ways that a classical system has trouble with, but we are interested in efficiency not novelty.
Not that I am the sole or most important person to convince but, to convince me of the merits of the system I would think that a proper BSFC map covering the whole range of operating points would do it. This could be compared to similar engines (not that I have found many that fit).
Another interesting tech I have been reading about lately is supercritical fuel injection...
Honestly I am still undecided if the revetec bottom-end actually does exhibit novel combustion characteristics but if it does, then it would be quite interesting to see how supercritical fuel injection effected the combustion process.
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Sersiously man, stop it :(
You think that a company ( esp a smallone ) is viewing it's web page daily ?
As I'd suggested, go look around t'internet. I guarantee it will take 1 minute to find an out of date quote not "replaced" :)
Thankfully Brad doens't have to convince you with theories and seems he's working on doing it practically. I'll always lay my money on a guy putting the theory in it's right place and building it to prove it. Theory debunking is too easy :(
So I think we've gone round the tech in this thread and abused Brad so much I doubt he'll bother to return and am happy to wait and see what comes from the current set of tests.
re supercritical , check out the work couple of years back at UCL in London, though that was diesel. Is it now coming up in petrol ??? WHy not go kick off a thread on that if you want discussion
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Seriously?
Of course the internet is not updated completely in real time... not the issue.
? Of course Brad doesn't have to convince me with theories... I'm convinced by data. But again I already mentioned the whole "I'm not the one who needs to be convinced" caveat. Simply an interested engineering student.
I think you mean dismissing theories is too easy... Debunking/disproving hypotheses and theories is what science is all about (at least from one philosophical point of view, anyways).
I too disagreed with the ridiculous economics/whining phase... I liked the actual technical stuff although we didn't exactly get anywhere. Still looking forward to Brad's white-paper whenever that gets finished.
Unfortunately I can't enough info about the whole supercritical fuel injection idea to start a new thread. Chemical engineering isn't one of my strengths and while I think I grasp the general premises of why supercritical fuel injection might be advantageous, it mostly goes straight over my head at the moment... :o
Still as for technical discussion. You have taken on quite a defencive position but knowing you (however little I do) I think you have your own reservations about the mechanical design.
It would be interesting to see your biggest reservations.
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HT, are you familiar with this graph?
[IMG]http://img.photobucket.com/albums/v314/Quicksilver4000/Untitled-1-3.jpg[/IMG]
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Nope can't say that I am Kozy, should I be?
Some sort of torque or acceleration graph?
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I'm guessing hydrocarbon emissions, but would be interested if it pertains to the Revtec in any way.
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ht, you got my points on theory the wrong way round.
It was your theory based posting over the years that has worn me down :)
Brad seemed to try to give practical info on what he could share and you were using theories based on classic otto derived info to try to attack him and his designs.
But putting that aside, my reservations are as they always have been.
That there is a corner condition happening ( maybe even a chaos-theory-surface ) and whilst points and small regions can show the real benefit the application across the wider solutoin may show up it's limitations.
As I said, tho', I am a resaerch and development supporter and prefer practical attempts rather than theoritcal blockages. Spending 30 years in HP research does that to you. Saw many products that fundamentally changed electronics and measurement that started out ignoring current theory and plugging away on the wild idea !!
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"Theory based posting"?
The problem was that Brad didn't just give practical data that could then be discussed. He gave theoretical explanations for the anomalous behaviour and didn't encourage open discussion of those theories. At least that is what I experienced.
I am pretty sure that when I tried to argue something for a theoretical point of view that I was using the basic laws of thermodynamics and not classical Otto theory...
It seems that you think I am anti-innovation or that I am stuck in the 1900's when it comes to ICE-theory, but that couldn't be further from the truth. I'm all about innovation. Why would I be trying to make my own engine if I wasn't?
My problem is with some of the explanations and theories that Brad is using to explain the novel behaviour of his invention. I don't agree with them because of what I consider to be a lack of compelling evidence, not because I am anti-innovation.
[quote=Matra]That there is a corner condition happening ( maybe even a chaos-theory-surface ) and whilst points and small regions can show the real benefit the application across the wider solutoin may show up it's limitations.[/quote]
That is the total sum of your reservations? I'm not quite sure what you mean by "corner condition" (subsequently "chaos-theory surface" makes no sense to me either). I assume that the later part of this quote means that you acknowledge that even though a single point of testing shows remarkable merit, a larger set of test conditions may find limitations.
No reservations about any of the claims? mechanical design? Brad's thermodynamics theory?
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ht, by the terms I am referring to the sudden change nature of many near closed loop systems and they underpin all modern improvements as we've reached an end point in classic math application in theory and practice. Read any of the chaos theory tratise academic books -- damn I've lent mine out and cant give ISBN.
Basically that the world is not running to linear relatioinships but may LOOK as if it is, but only because we've not seen/experienced the interation of the linear elements coming into a combination which introduces an anomoly.
Some of these are only "corner conditions" eg the appear in one place, have one outcome.
MANY hoever are turning out to be "chaotic" but using new math can be "semi" predictable.
Best simpel explanation in the early books is think of a mathemtaical curve, now add third dimension and we have a plane of outcomes. Now rather than jsut introducing peaks and troughs across that plane, BEND it so that now it in some way folds over/above/below in certain regions. NOW when a soltuion space stays away from the edges of the fold it's very predictable. BUT at the fold the solutions show rapid change and at some point "drop" off the curved edge and in classic math/analysis seems random.
IN chaos-theory math you can follow the path of solutions along the lower end of the fold. It requires multi-dimensional math theory AND is mind blowing. Ex colleague was in a math research group in HP and used to try to explain to us how 7th dimensional math worked as it was half way to the domain his research was in. SCAREY PEOPLE :) :)
Anyway, get a proper academinc book on chaos theory math and I think it'll be clearer as my explanation is far too simplistic and in terms *I* understood it by which mate kept telling me that I "wasnt quite right, but close enough to now go the the 5th dimension math". He WAS a smug bar steward :) :)
re the last Q and Brad's then no I think we covered the issues well on the mechanical design and the possible weak areas and esp friction surfaces ( remembering it off the top of my head I'm NOT going reading back the history ) but on his thermo theory I coudl see analogies with other domains where multi-dimension math has shown our limitations of thinking in our own classic ways and the info presented was valid in the context given. NOT that I want to go back over it all again as we'd all really like this thread to go quiet till we get info from Brad or others who are usign te Revetec design base and have insights based on real rather than guess or opinion or application of classic theories without mind-expanding drugs :) :)
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[quote=hightower99;957566]Nope can't say that I am Kozy, should I be?
[/quote]
If you're not familiar with it and the way it is derived, then I'm afraid you are not qualified enough to shoot down Brads design.
I studied this engine design for my dissertation project at university 3 years ago, completely independant of any results Brad has posted and based purely on the geometry of the bottom end and it's effect on the adiabatic cycle and I can say that the calculated results indicated that Brads findings are entirely plausible. Compared to a crankshaft engine of the same bore and stroke, this design is theoretically capable of a big increase in effeciency.
What I can only prove on paper, Brad appears to have proved in practice.
It's been a while since I have posted here, but from what I recall, you can offer NO weight to your arguments against this design, only armchair theory.
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[quote=Kozy]If you're not familiar with it and the way it is derived, then I'm afraid you are not qualified enough to shoot down Brads design.[/quote] Seeing as it is just a graph with no title or axis values what exactly did you expect from me? Did you expect that I could visually match the shape to a function in an ICE and then from the unnamed axises determine what exactly the graph showed?
[quote=Kozy]I studied this engine design for my dissertation project at university 3 years ago, completely independant of any results Brad has posted and based purely on the geometry of the bottom end and it's effect on the adiabatic cycle and I can say that the calculated results indicated that Brads findings are entirely plausible. Compared to a crankshaft engine of the same bore and stroke, this design is theoretically capable of a big increase in effeciency.[/quote] First what do you mean "Brad's findings"?
Secondly the geometry of the bottom-end is highly variable within any given set of design conditions leading to highly variable effects on the thermal cycle. So unless you proved that some more efficient movement form is possible with a revetec style bottom-end whilst being impossible to achieve with a classic bottom-end, I don't see the point.
Thirdly when comparing efficiency between two different bottom-ends you need to look at more than just the geometry and theoretical torque output. One of my biggest concerns is the increased complexity, friction area, gears ect. of the revetec design compared to the classical design. Hopefully you included those factors and more in your consideration.
[quote=Kozy]What I can only prove on paper, Brad appears to have proved in practice.[/quote]So far only at a single specific point though...
My arguements against the design are purely mechanical. As for Brad's theories about combustion engine efficiency I'll have to wait until his white-paper is available.
Are you able to share your dissertation project? Privately perhaps?
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[quote=hightower99;957962]Seeing as it is just a graph with no title or axis values what exactly did you expect from me? Did you expect that I could visually match the shape to a function in an ICE and then from the unnamed axises determine what exactly the graph showed?[/quote]
Yes I did. The whole purpose of posting the graph, which I made especially without any labels, was to assess your level of understanding.
[quote=hightower99;957962]
First what do you mean "Brad's findings"?[/quote]
It's been a few years since I paid any attention to this stuff, so it may be out of date now, but I recall he was claiming an increase in efficiency of around 30% over a traditional design. The results of my analysis showed that this was entirely possible.
[quote=hightower99;957962]
Secondly the geometry of the bottom-end is highly variable within any given set of design conditions leading to highly variable effects on the thermal cycle. [/quote]
I don't understand the point you are making here.
[quote=hightower99;957962]
So unless you proved that some more efficient movement form is possible with a revetec style bottom-end whilst being impossible to achieve with a classic bottom-end, I don't see the point.[/quote]
That's pretty much what I did.
[quote=hightower99;957962]
Thirdly when comparing efficiency between two different bottom-ends you need to look at more than just the geometry and theoretical torque output.
One of my biggest concerns is the increased complexity, friction area, gears ect. of the revetec design compared to the classical design. Hopefully you included those factors and more in your consideration.[/quote]
You are of course completely right here, however this was beyond the scope of my project, I was simply analysing the design with respect to its affect on the thermodynamic cycle. I would have liked to have gone further but time constraints tend to restrain how far you can go with these things.
[quote=hightower99;957962]
My arguements against the design are purely mechanical. As for Brad's theories about combustion engine efficiency I'll have to wait until his white-paper is available.[/quote]
You may have some good points, but as far as I am concerned, with the gains Brads design is theoretically capable of producing in terms of combustion efficiency, he can afford some extra mechanical losses, so long as the the gains exceed the losses, then it is still a valid design. If you are going to put an argument up then you're going to need to start backing up your theories. Calculate some theoretical friction losses, some bearing loads, rotational masses and engine harmonics, and compare them to a classical design. Prove to yourself that this doesn't stack up, then put your argument forwards.
[quote=hightower99;957962]
Are you able to share your dissertation project? Privately perhaps?[/quote]
Sorry but I am not prepared to share it, not only does it contain specific design information about the trilobes granted to me personally by Brad, but it also represents a year of hard work sat infront of speadsheets and CAD programs designing and analysing the concept. I hope you can understand that its not something I am willing to give up to someone on the internet.
Now maybe if you come back having calculated the theoretical mechanical losses, then we could have a proper techincal discussion about the gains versus the losses... ;)