IC Engine Testing

In article , Andrew Mawson writes

Thanks, Andrew. Bill Galvin actually looked at these and found the compression ratio was very low; we have it in reserve (to modify to increase comp. ratio) if the other ideas do not come together.

David

No; compressing the spring is useful.

Gas is an extremely inefficient spring, as it compresses adiabatically, loses a large part of the heat and thus of the pressure.

Temperature does not seem to be a serious problem for the titanium used. Weight is also not a problem (though adapting it to small pistons in low-cc engines is a pain). I agree fatigue life needs to be proved in practice, and that was one of the main purposes of the tests I originally mentioned.

Don't need to, it has circular symmetry.

Why do you think it does this rather than compressing? The oil seal would probably stop its passage.

Thanks for your input. However, recall how may scientific man-years were spent proving insects could not possibly fly? Maybe we can convince you with a test one day.

David

In article , snipped-for-privacy@bem.fki-et.com writes

What a wonderful site! Thanks for drawing it to our attention. However, I'm not sure I can see how this has any resemblance.

David

Wayne,

Yes, sorry I missed commenting on it. I have passed that one on, as I don't know if we know them or not!

Thanks

David

I couldn't, see my other posts. Well, telling the truth, I think it is nonsense.

One more thing. Water brakes are often combined with some kind of electric brake, bcause the water brake have a very sensitive characteristic (someone said that already in an other post).

Nick

Na, you should look at pistons out of engines that are not el cheapo designs. Either high power or high efficency.

If it does compress the air in the piston (there is a change of volume), and the air can't pass, you will have different losses.

We will see ...

Nick

That was because of the con rod with a link in it (I have mentioned that). Took some time for me to understand what David wanted to say with the Atkinson. Yes, what I meant looks a bit like that, but it is also quite different. Gears with links have the property of changing their behavoir dramatically if you change the geometry a bit.

Nick

Had a look at that site right now. The book you are talking about is the one from Gingery, I think. I have that book and it is as scientiffic as Gingery can be (read: zero). "Internal fire" from Cummins has a better description and more background.

In a period of mental confusion (I really don't know what for I did that) I wrote a script about that engine. When I realized that it has no use, I stopped it (3/4 finished). If I can find it again, you can use (if you want) the part of the Atkinson Cicle Engine's history and motivation.

Nick

I think congratulations are in order, these people have come up with something other than magnets or tin balls!, strangely they seem to have stuck with the same 30% figure that's often claimed for those 'remarkable' inventions 8-).

Of course what's truly remarkable about this invention is that the engine companies haven't thought of it, especially when they're spending millions on engine improvements that only return a tiny fraction of this invention's benefits...

Greg

Yes, and did that patent agent get a fat fee for it?, I've seen recent patents for things that have been in the public domain for decades and therefore aren't worth the paper they're written on, it didn't stop some patent agent taking his cut 8-).

Greg

Tell me about it LOL.. We found that at certain times just the tiniest movement of the valve would either stop the engine or allow it to overrev, doesn't say much for the engine though does it LOL....

The company I was involved with installed a 12Kw Magtrol later, well actually I installed it! This was very sophisticated with PID closed loop. But even then the terms would have to be altered for different engine characteristics. That dyno cost 16,000 UKP if I recall correctly.

One of the reasons I suggested a model aero engine, is they can be loaded quite well with a series of props. Alterations to the engine can be very quickly seen with just a tacho.. No good for part throttle testing though, this is where emissions really become an issue. I think the OP was suggesting emmissions benefits. Don't they all say that these days ;-) Don't take that as a critism, I'm just a cynical bugger!

One of these days someone's going to guess which company I'm refering too! Damn loonies LMAO....

Wayne...

Small Heenan & Froude dyno's are around, we have sold a couple in the past year or two.

We also have an electric dyno for our Ruston & Hornsby 1ZHR horizontal diesel, rated at 7kW it consists of a 220V dynamo mounted in swinging cradle bearings with tacho and fuel metering etc., so not too difficult to knock up.

I'd have thought that a DPX3 H&F would be available at less than a couple of grand secondhand.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

I could make a comment on the miniscule resources needed to fund a suitable engine dynamometer and engine test program and the total lack of a clue from the designers/funders on these issues .....but I won't. :)

If it really was any good AE would have had the resources to get it to work. As another poster has already mentioned it's just a tweak/variation on the Atkinson cycle.

Looking at that design I don't hold any hopes out that in service this is going to coke up and stick in one position or another.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Sign of a demented mind answering ones posts

Anyone have an idea of under piston temperatures? High enough to draw the temper from a spring ?

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

---Snippage---

Looking at the piston design in the patent, I'd figure that a couple decent backyard mechanics that were living down the road from a decent wreckers yard could build up a car engine on the principle in short order. Fabricate the pistons, thow them onto a set of somewhat shorter than stock rods, and have at. I doubt they would bother, unless they could soak someone for the costs.

Lesse, more weight, more moving parts (titanium, yet, as if that is going to solve any problems) Springs that wont last long either. The whole secondary piston is in a hot dry location, with no provisions to keep it lubed other than splash past the wrist pin. I see that as a recipe for burnt crusty oil bunging up the works further.

Given the example touted of reasearch proving bugs couldn't fly, I'll wager that the proof of concept ends up showing the same type results as the bug researchers had.

In the bug researchers case, in spite of evidence that was quite clearly contrary to their findings, they declared that bugs could not fly based on incomplete and erroneous data input into their research. So much for proof.

I see no way that having one further place to expend energy will develop into an increase in operating efficiency. Frictional losses from compressing the spring and having it rebound, plus the extra weight of the pistons lead me to conclude that the fact that the example engines run at all is more a testimony to the wide range of the operating envelope of the internal combustion engine, rather than any miracle of design in this part.

Most of the efficiencies of this particular design appear to relate to it's ability to efficiently transfer funds from the pockets of the investors to the pockets of the employees of the inventor.

If 'twere me, I'd look to be there on salary rather than as a percentage shareholder.

But hey, prove me wrong! When a couple independant labs announce to the world that a new engine is going to change everything, I'll change my tune. Till then... Dreamers.

Cheers Trevor Jones

From Heywood's Internal Combustion Engine Fundamentals - typically about 200 deg C on the skirt and in the area of the gudgeon pins, around 250 deg C above the top ring, 280-300 deg C on the crown.

So the spring is probably safe :)

In article , Peter A Forbes writes

Peter, thanks for the suggestion. Will follow up tomorrow, it's 1 am now!

David

In article , Martin Evans writes

Won't work with coil springs, not stiff enough.

I may have misunderstood the Atkinson cycle demo in the nice graphic website, but it doesn't look at all the same to me.

Thanks anyway.

David