Rotary valves

[Anatol]

Hi
my first post after my introduction I'm going to try to keep my questions distinct in separate threads.
I've been thinking a lot about valves and how to drive them. Everyone seems agree that valve systems are fundamental. I get that.
Rotary valves seem to have a lot going for them - simple to make and drive. But I read a provocative quote from Tom Kimmel saying everyone discovers rotary valves and thinks they're the solution, but they seize when hot and leak when cold. But surely the Corliss valves were (reciprocating) rotary, and they worked pretty well. I see there has been a long history of research in IC engines. What is your opinion of Kimmel's argument, and there a new material solution that would solve it? ie something with high lubricity and minimal thermal expansion, (like a ceramic)?
thanks!

 

[lohring]

Take a look at all these designs over the last 100 years or so. If any worked better in the early IC engines you would have seen them in a production engine. The early steam engines were inefficient, relatively low pressure engines. Oil could be added to the steam for lubrication. As pressures rose leakage became more of a problem. Early IC engines had a lot higher pressures and temperatures to seal against. Smart designers looked at high pressure steam engines and picked poppet valves. In IC engines only the single sleeve valve was a serious challenger to the poppet valve. Designers haven't given up, but no other challengers have emerged. Tom Kimmel is right. There are valves that leak and poppet valves

Lohring Miller

 

[Anatol]

Lohring
thanks for your reply. I know the museum of retro technology and had reviewed that page Yes its hard to argue with lack of long term success. Still, some dream
So higher pressure is the issue. Out of interest, where would you put the pressure limit for a rotary valve?And what about the Corliss? Wasn't it relatively high pressure?

Thanks for the tip on sleeve valves. I did some reading. It seems they were used exclusively for IC. It wasn't clear but it seems they were 2 stroke. There was references in a page to the N marking of the piston on the sleeve wall. (Combination of rotation of sleeve and recap of piston. It made mer think that a reciprocating sleeve would also be possible. But then - that would essentially be a piston/spool valve / slide valve hybrid.

Does anyone know of sleeve valve experiments with steam?

 

[lohring]

When I was young and seriously into engineering, I hung out with an heir to the Quaker State oil fortune. He was trying to get a rotary valve four cylinder engine to work well. Needless to say, it wasn't successful. I'm not sure what steam pressures rotary valve engines were used for, but the last 700 to 1000 psi piston engines in cars used some type of poppet valve.

Single sleeve valves were developed by Sir Harry Ricardo in England between the world wars. They were the single sleeve, Burt-McCollum design and had several advantages over poppet valves with the low octane fuels of the era. [ame="https://www.youtube.com/watch?v=rUVUuTsa3TQ"]This video[/ame] shows how it works. Bristol and Napier used them in aircraft piston engines very successfully. Many of the new design proposals for big, high power aircraft piston engines used them. Turbines ended all that and better exhaust valve technology along with high octane fuel eroded their advantage. They still fascinate me as a designer. This is an excellent model version.. Sealing especially in aluminum cylinders over wide temperature ranges was still an issue.

Lohring Miller

 

[Anatol]

Thanks for that. I read some about Ricardo and the Burt/McCollum design. The video shows the sleeve rotating and rising and falling. Is that required? Surely a rotating (only) sleeve would provide inlet and exhaust, with one port, and with inlet and exhaust at different locations on the block for timing (I'm thinking for steam here, 2 stroke). Even a double acting, with manifold/galleries in the block...

 

[Anatol]

The model (and the shop) at http://www.metallmodellbau.de/Sleeve_Valve_Engine.php
was very nice.
there's a bunch of good stuff in German and French, I know, sadly I don't read either well enough.

 

[lohring]

One of the reasons the single sleeve worked well is the combined motion helped with lubrication and to distribute heat into the cylinder. Even with the two stroke sleeve Ricardo felt that some rotary motion was needed even though a straight reciprocating motion was all that was needed for port timing. Google translate helps with pages in other languages. If nothing else it provides humor when trying to translate technical topics. Ricardo's book, The High Speed Internal Combustion Engine, is by far the most readable engineering text I've read. It's an excellent history of the British development of IC engines. I have both the original hard cover edition I bought around 1960 and a paperback reprint. It's hard to beat the large fold out blueprints in the original.

Lohring Miller

 

[Anatol]

Lohring
thanks for the Ricardo recommendation,mendtion and kudos to him for writing a readable engineering text. He must have been a renaissance man!
I get the heat and lubrication issues. I've spent a lot of time in the museum of retro technology lately, examining all the various permutations of steam engines, and IC engines, that didn't succeed. More on this in another thread.

 

[Anatol]

go to Uniflow compound engines