Hey guys, I'm wondering if anyone would have an idea what the temp of the internals of a turbo'ed Rotary would reach under extreme loads? Rotor faces, side irons, apex seals, rotor housings. Just want to get an idea, thanks.

 

This has been documented in SAE papers for only stock engines.


-Ted

 

Cool, have a link or know the numbers off hand?

 

million degrees

 

Something between the EGT and the oil and water temps, depending on how close/far it is from each.

 

oh, so between 180 and 1800.. that narrows it down hah.

 

Well it's a pretty big spead of components he listed.

Close to the edge of the coolant passages the metal will be close in temperature to the coolant, close to the combustion chamber it'll be closer to the EGT temp if it's in the area that sees exhaust gas, and it'll be cooler where it sees only intake air/fuel. So on the housings/irons the temp will be varied all over the place.

For the rotors they're seeing cooling oil inside all the time, then on the outside it'll vary and be cooled and heated by the cyclic combustion. There'll also be some variaton with the trailing edge probably getting hotter, as the charge will tend to collect there moreso than at the front. If it's the apex seals they'll probably get hotter due to them being farther from the oil.

 

Taken from SAE papers...

First pic comparing Fe versus Al rotor housings.
You can pretty much ignore the line for the Fe housing.

Second pic of apex seal temps over varying RPM's.


-Ted

 

Taken from "Rotary Engine" book written by Kenichi Yamamoto in 1981.


-Ted

 

Nice, so we're talking absolute worse case 300*C. Thats not bad at all.

Thanks Ted!

 

Flash flame temperatures will be a lot higher than that, however it happens to quickly for anything to absorb that kinda of heat..

 

anyone ever heard of someone installing a CHT probe into a rotor housing. Pretty common on Aircraft piston engines. I guess it could be drilled between the spark plugs.

 

Why?
I would think an EGT set-up would be superior and react a whole lot faster...

Besides, all Kouki FC and FD rotor housings have extra bungs for the knock sensor right above the two spark plug locations...


-Ted

 

That would be a useless place to put a CHT probe. The hottest portion of the chamber is TDC and afterwards. CHT probe could be located between the plugs if it were feasible for the rotor housing to accept it.

B

 

do they make temp probes that are a little more resilient than the normal egt probe?

ie something that if probably prepared for, would withstand combustion pressures directly. Im not talking of having it stick out in the chamber, but if it could sit flush with the housing face, atleast it would be better than mounted on the outside of the housing, being affected by the coolant even more so

 

hot as the fires of Mordor

 

The apex seals or a little inward of them has got to be the hottest part, since that's the point that's furthest from the oil or coolant. So I'll bet Ted's graph is right on the money for the highest temp. The housing should be basically the same temp as the coolant, and the rotor temp should vary between the oil temp and the apex seal temp.

I had a materials professor that was designing lightened piston pins. He and his buddy were really stuck on the problem. Aluminum pins didn't have nearly enough surface hardness. Then he asked someone the temperature of the pins and the engineer told him they were about the sam temp as the oil. Then it just clicked. He made the pins out of a composite (similar to fiberglass or carbon fiber) and stuck a hard steel sleeve on them. The thin steel sleeve weighed as much as the composite insert. My professor said he nearly cried when he had to use that sleeve. Then the company scrapped the project due to the cost of the pins. $1 vs $0.10 or something like that.