Oddball engines and prototypes

[Frits Overmars]

I agree with your ideas (can't beat the round pistons and rings) and the inlet and exhaust kept relatively seperated - very compact compared to an opposed piston design like the Junkers Jumo with the inlet at one end and exhaust at the other plus two crank assemblies - but it does still introduce some more complication of course. It would need some specialised machining facilities for the cylinders, but not too complicated really and of course the rings might need slightly curved faces...
BTW Frits are you still in country "I"?

No, I'm back in country D, thanks for asking Will. Spent some great time in Italy with my friend Andrea degli Esposti of DEA fame and two German friends who are now trying to learn Italian.
Round pistons and rings are fine, but donut-shaped cylinders are anything but, and you are quite right about the rings needing 3D-curved faces, unless they are very thin, in which case they could wear themselves to the required shape. And they should not be allowed to rotate at all. But for a two-stroke that would not pose an additional complication.
For an opposed-piston engine without the Junkers Jumo-complication of two crankshafts, below left, you might want to take a look at the DKW below right.
Its crankshaft and con rods resemble those of the James clap-hands engine, but the Deek's cylinder is straight(forward). Comparatively KISS, I'd say.

[guyhockley]

Basically, you've already summed up all the relevant facts. Jerry likes to think and thinker out of the box. The above Folan-KTM is just one example. It ran, once, and then it was shelved; on to the next project. Lately he seems to be concentrating on Yamaha XS650 engines for MX sidecars.

Thanks, Frits. Shame he didn't fiddle with it a bit more...

[WilDun]

Round pistons and rings are fine, but donut-shaped cylinders are anything but, and you are quite right about the rings needing 3D-curved faces, unless they are very thin, in which case they could wear themselves to the required shape. And they should not be allowed to rotate at all. But for a two-stroke that would not pose an additional complication.
For an opposed-piston engine without the Junkers Jumo-complication of two crankshafts, below left, you might want to take a look at the DKW below right.
Its crankshaft and con rods resemble those of the James clap-hands engine, but the Deek's cylinder is straight(forward). Comparatively KISS, I'd say.

From the picture, it looks to me that this DKW (which I had never heard of before) has the same layout as the successful opposed piston Commer TS3/4 engines used in medium sized trucks in Britain, this of course was probably a copy? or perhaps even (originally was) a German Sultzer engine, war booty maybe? - I dunno. but it was discussed earlier on in this thread.

Guess this layout makes for a very compact engine despite the fact that it had an external blower instead of using the crankcase as a pump.
I know that it was also very smooth runner, I had an 80 mile trip in one when I was a teenager.
However I don't think that it would be much good for competition, (ie the engine layout, not the truck) those huge rockers would limit revs drastically I reckon.
It seems that one of the big American companies bought out the Rootes Group (including Commer) and canned this engine, so that was the end of that!

[Frits Overmars]

From the picture, it looks to me that this DKW (which I had never heard of before) has the same layout as the successful opposed piston Commer TS3/4 engines used in medium sized trucks in Britain, this of course was probably a copy? or perhaps even (originally was) a German Sultzer engine, war booty maybe?

The text plate in the above DKW picture states 1938, which could make it 'available' as a war booty for Commer.
While searching for the Commer, I not only discovered that it was post-WW2; I also found that Sulzer is Swiss, not German ( https://en.wikipedia.org/wiki/Sulzer_ZG9 )
so the Sulzer couldn't have been a war booty.

Some more opposed stuff:

And some more: https://www.google.de/search?newwind....0.pNAAugLz4ns

[WilDun]

The text plate in the above DKW picture states 1938, which could make it 'available' as a war booty for Commer.
While searching for the Commer, I not only discovered that it was post-WW2; I also found that Sulzer is Swiss, not German ( https://en.wikipedia.org/wiki/Sulzer_ZG9 )
so the Sulzer couldn't have been a war booty.

The text plate in the above DKW picture states 1938, which could make it 'available' as a war booty for Commer.
While searching for the Commer, I not only discovered that it was post-WW2; I also found that Sulzer is Swiss, not German ( https://en.wikipedia.org/wiki/Sulzer_ZG9 )
so the Sulzer couldn't have been a war booty.

I always had thought that Sultzer was German (probably because most Swiss people I knew spoke French)!
This layout I believe was being eyed by a lot of people in various countries but the Brits managed to get it successfully into production (then scuppered by the Americans) who were getting out of two strokes, this I feel was a big blow to the two stroke cause!
In Britain Napier developed the Junkers Jumo further (they already built them under licence pre war) into the Deltic, which (to me) was a horrible looking thing, but it was used very successfully for many years, mainly in Locomotives.


Talking about horrible looking things, how about this one which is being hailed as a "great breakthrough", my feeling is that it won't be successful as the Napier Deltic!
Attachment 332823

[ken seeber]

Will, I remember the Commer TS3, for some reason over here called the "knocker". It had a really good exhaust sound though.

As to any toroidal arrangement, then I personally don't think they're viable, just for the mfg. perspective. As to the "square "clappers", then I also give them a fail, for the reason of trying to seal square corners. Working at Orbital on the original Orbital orbiting engine, apart from the fundamentally lousy combustion chamber shape, was the "cylinder sealing", reflected in huge amounts of blowby.

Dunno about you, but I reckon that the only ICE engine format (2 or 4 stroke) will be the current conventional format PRIOR to the electric drive era.

[tjbw]

...

Talking about horrible looking things, how about this one which is being hailed as a "great breakthrough", my feeling is that it won't be successful as the Napier Deltic!
Attachment 332823

I get "invalid attachment"?

Do you have another link to the breakthrough?

[Frits Overmars]

Will, I remember the Commer TS3, for some reason over here called the "knocker". It had a really good exhaust sound though.

Poppet exhaust valves have an initial opening speed of zero, so they don't stand a chance of generating a powerful exhaust pulse, compared to an exhaust port that's being opened by a piston moving about 50% faster than mean piston speed. You could say that such a port opens with a bang .
That's the reason I love the sound of a Wankel, even though it's a four-stroke: http://www.youtube.com/watch?v=9jAngoCbOMg#t=0m8s

Dunno about you, but I reckon that the only ICE engine format (2 or 4 stroke) will be the current conventional format PRIOR to the electric drive era.

Same here. Though we may see free-piston engines (with cylindrical pistons) combined with linear generators, until batteries or fuel cells have matured.

I get "invalid attachment"?

Same here again.

[WilDun]

Will, I remember the Commer TS3, for some reason over here called the "knocker". It had a really good exhaust sound though.

As to any toroidal arrangement, then I personally don't think they're viable, just for the mfg. perspective. As to the "square "clappers", then I also give them a fail, for the reason of trying to seal square corners.
I reckon that the only ICE engine format (2 or 4 stroke) will be the current conventional format PRIOR to the electric drive era.

Yes Ken, I would tend to agree with you on these matters and I am glad your last sentence was included - Being positive (as trendy people actually seem to believe these days) is not about pretending that something is not happening, positive to me is addressing the problem and either dealing with it or facing the inevitable and moving on - however, swimming against the current can be a helluva lot of fun, so let's deal with anything trying to kill the two stroke!

tjbw
Sorry I've been away for a few days - I'll sort out the pic somehow so you can see the engine I was meaning - but here's a link instead, to save any trouble!
https://thekneeslider.com/ecomotors-...osed-cylinder/

Frits,
I think the free piston engine/generator looks very promising ( at least till they get small turbine engines sorted) but why is development taking so long for the free piston ??- got to be a reason!

[WilDun]

This is the offending picture (OPOC)

[Frits Overmars]

Frits, I think the free piston engine/generator looks very promising ( at least till they get small turbine engines sorted) but why is development taking so long for the free piston ?

I dunno. Free piston engines have been around forever, mainly as gas generators for turbines. Notably the French have been concentrating on them.
Maybe the need for on-board electricity generators has not yet become urgent enough.

This is the offending picture (OPOC)

I like your wording Will. How do you make a two-stroke engine more complicated than a four-stroke? The OPOC answers all your questions.
By the way, it's not a free piston engine, with all those con rods.
Initially, one Bill Gates financed the OPOC, proving that he knows more about computers than about engines, but then he must have seen the light through his windows and withdrew from the project. The Ecomotor company seems to be carrying on, describing their efforts in the hot-air style that appears to be normal in the USA but that never fails to irritate me. Well, at least they manage to generate hot air without free pistons.

[lohring]

A model boat racing friend of mine once worked for the predecessor of Eco Motors. He was excited about the possibility of a small version with a piston compressor on the base of the outboard pistons. See the pictures. I don't think they got the reed valves to work , though. I always liked the electrically boosted turbocharger they developed. That looks like the answer to the bigger two stroke engines with isolated crankcases. It should be a lot better than roots blowers.

Lohring Miller

[WilDun]

A model boat racing friend of mine once worked for the predecessor of Eco Motors. He was excited about the possibility of a small version with a piston compressor on the base of the outboard pistons. See the pictures. I don't think they got the reed valves to work , though. I always liked the electrically boosted turbocharger they developed. That looks like the answer to the bigger two stroke engines with isolated crankcases. It should be a lot better than roots blowers.

Lohring Miller

Lohring, I have been toying with my own ideas on the elusive "perfect two stroke engine" and there is one quite similar idea in that engine (which I had firmly believed was my own).
I'm not interested in using that whole layout though (don't like it at all), just one of its features.
Is it a case of "great minds think alike" or "fools seldom differ" ?

[husaberg]

Lohring, I have been toying with my own ideas on the elusive "perfect two stroke engine" and there is one quite similar idea in that engine (which I had firmly believed was my own).
I'm not interested in using that whole layout though (don't like it at all), just one of its features.
Is it a case of "great minds think alike" or "fools seldom differ" ?

1978 Motobecane 99Z.

[WilDun]

[QUOTE=husaberg;1131066626]1978 Motobecane 99Z.

That one, also another one ( I think from Montesa), which had the piston pump stuck out the front (90deg to the cylinder).
But, I was looking at and would be very interested in straight line operation of a piston rod (this was discussed to death a while ago) - I would never think of going oilless though!