Otto Lutz's Swing Piston Engine

[Cuirassier]

I was looking at unconventional IC engines when I came across Otto Lutz's swing piston engine.
Contemporary German turbines were having trouble coping with high temperature produced by the combustion chamber. To solve this problem Lutz's engine was supposed to be put in as a gas generator. It would extract some work and cool the heated mixture so that the turbine could handle the heat.

Does anyone know how it actually worked? I have looked at Lutz's patent but couldn't tell how it would operate.
Here is a drawing

If the German designers had dropped the turbine instead using only Lutz's engine to do work, could the resultant machine have functioned like a turboprop?

 

[Deleted member 68059]

I was looking at unconventional IC engines when I came across Otto Lutz's swing piston engine.
Contemporary German turbines were having trouble coping with high temperature produced by the combustion chamber. To solve this problem Lutz's engine was supposed to be put in as a gas generator. It would extract some work and cool the heated mixture so that the turbine could handle the heat.

Does anyone know how it actually worked? I have looked at Lutz's patent but couldn't tell how it would operate.
Here is a drawing

If the German designers had dropped the turbine instead using only Lutz's engine to do work, could the resultant machine have functioned like a turboprop?

I dont really know what the image from Wiki you posted is, because it certainly isnt a "Swing Piston Engine". That is a rotary compressor.. NOT a swing piston engine. The
people who wrote the wiki article seem to have got a bit confused. I`m not sure if you`re interested in the rotary compressor in the picture or in the ACTUAL
swing-piston engine... but anyway.

Otto Lutz`s real swing piston engine:

(Basically none of the stuff like this ever works well because its immensely difficult to get the tolerances to work properly and any "theoretical advantages" usually
never manifest on test because it either wears out too fast or has so much friction and losses that its no better than something 10x simpler).

 

[Cuirassier]

That is a rotary compressor.. NOT a swing piston engine.

Couldn't this compressor, if used in the opposite sense, extract energy from the hot gas?
Lutz's description of his compressor is not clear to me. US2301667A - Rotary compressor and other engines - Google Patents

I`m not sure if you`re interested in the rotary compressor in the picture or in the ACTUAL
swing-piston engine

I didn't know how a swing-piston engine looks. My interest is in plausible engines that could have been made had the jet engine not been invented.

Rotary mechanisms, like Lutz's, should be capable of handling speeds in great excess of piston engines. A multi stage compressor combined with a rotary compressor (working in inverse) should theoretically work. The engine could power a propeller (similar to a turboprop) or act like a turbojet.

You mentioned fast wear out. Am I correct to assume Lutz's compressor couldn't substitute for a turbine for the same reason?
I imagine if this compressor were to move at speeds comparable to a turbine's it would wear out very quickly.


The engine above seems simpler to seal than a Wankel engine. The pistons are smooth surfaces with no sharp points touching the chamber wall.

 

[basil]

Cuirassier,
I recommend Kay's book where you will find a detailed description of the Lutz gas generator and its intended applications (5000 hp turboprop and turbojet) as well as construction efforts.
Amazon product ASIN 184037294X
View: https://www.amazon.co.uk/dp/184037294X/
As Calum mentioned the drawing in Wikipedia has nothing to do with the Lutz design.

 

[basil]

As additional information: in Germany there were several attempts to replace the constant pressure combustion chamber of a typical jet engine by a constant volume combustion process to increase the efficieny of the combustion. The Lutz concept was a possible way to achieve this by replacing the combustion cans or annular combustion chamber with a torroidal piston system.