New Engine ?

[GORDON STREETER]

http://www.dlr.de/dlr/en/desktopdefa...318//year-all/

[Al Weyman]

Interesting.

[grantp]

No point really.

Steorn are years ahead of the field with the Orbo technology.

Really.

[JohnD]

Opposed piston engines been around for a while, free piston engines not quite so long but still since the 70s, I think.

This company seems to be selling one, since 2007:
http://www.freepistonpower.com/

John

[GORDON STREETER]

Yes I know that opposed piston engines have been about for years, I used to work on the TS3 Commer engines when I left school 50 odd years ago but this is a different slant because the pistons are not connected to a rotating crankshaft but are controlled by gas.
Of course its still an ICE that uses a combustible fuel to produce electricity so it's not "ground breaking"
What I have found is that most of these things have been tried years ago and failed but with modern technology has shown a resurgence in these old ideas.

[wolfhound]

Originally Posted by GORDON STREETER

http://www.dlr.de/dlr/en/desktopdefa...318//year-all/

I suspect that an engine of this type woud have much reduced friction losses plus be a lot lighter with less components giving it a lot of theoretical advantages.

[JohnD]

Thanks, Gordon!

What puzzles me is how the opposing pistons in this design recompress the next charge. From other designs, the expanding charge compresses separate, inert gas chambers, or chambers joined for both pistons, in effect a gas spring?

That would be reaching the limit of the energy return, just as the two pistons approached each other, whereas a single piston, or opposed pistons driven by a crank shaft and the energy stored in a flywheel will have more than enough stored energy to recompress the chamber as much as required.

John

[Lancsbreaker]

Yes, interesting...Couldn't work out from the video clip quite how inlet and exhaust were managed, but I'm sure cleverer brains than mine have it worked out....

[Dave Brand]

Originally Posted by JohnD

What puzzles me is how the opposing pistons in this design recompress the next charge. From other designs, the expanding charge compresses separate, inert gas chambers, or chambers joined for both pistons, in effect a gas spring?

It has gas springs under the pistons. By controlling the gas springs they can, in effect, vary the compression ratio to allow the use of different fuels

Originally Posted by Lancsbreaker

Yes, interesting...Couldn't work out from the video clip quite how inlet and exhaust were managed,

Two piston-controlled ports, inlet on the left & exhaust on the right, take care of the flow of air in & out; fuel is injected directly into the cylinder. I'm not sure how they induce airflow, but as it fires every stroke of the piston they probably use the underside of the pistons to achieve that, just like a normal two-stroke.

EDIT: Looking at it again, it's apparent that the volume under the pistons is less than the volume of the combustion chamber. An external scavenge pump seems a more likely solution.

Maybe an old idea, but possibly one that was just waiting for developments in materials & control systems to be a practical proposition . . . or another academic dead-end!

[GORDON STREETER]

The TS3 engines that I used to work on 50 years ago were supercharged being two stroke and normal wet sump lubrication, that engine was very clever for its day and could probably be made to work very well now with modern technology.
One thing I do remember was it was a dirty job to decoke them !
http://en.wikipedia.org/wiki/Commer_TS3

[GORDON STREETER]

All this talk of a new design in engines to me means just “development” as I have yet to see any “radicaly different engines made from the beginning of the century apart from the rotary.
Slightly getting away from engines but still car related, back in the 70s I had a local customer that was a quite successful businessman (not in engineering) and he asked me to make up a test bed with an engine that he could use in his garage to develop a new “radical” automatic stepless transmission that he had brought the rights to, hoping to sell it on to a major car manufacturer and make his fortune.

I made up and installed the said test bed and then he asked me if I new any local engineers that could make up certain parts for the project.
As I had a mate with all the right machinery plus a newly installed spark erosion set up in his machine shop he was duly given the job and started post haste.
After making a load of these special bespoke parts that cost a fair bit I got to look at the drawings and parts as up to now it was all “top secret”.
I knew somewhere that I had seen a very similar thing and had a look in my old engineering books that go back to the 20s upwards and lo and behold I found the same type of drive that was fitted in a helicopter that was made to keep a constant speed from a variable one, not only was it the same it was also patented by Perbury !!!!!

A few thousand quid down the pan and a lesson learned !

[Al Weyman]

If it was a good idea why could the design be adabted to automobiles and Perbury paid a revenue for use of the design?

[dtype38]

Not overly convinced this engine is particularly compact. The schematics and models seem to omit any sort of induction system with filtration, cooling system or exhaust system. If you take all that off a modern IC engine they look pretty compact: http://www.ultralightnews.ca/sunfun0...hstaradial.JPG