Diesel Rotary??

[Dominic]

Just wondering why there haven\'t been any major developments into diesel rotary engines (or have there? :Hammer ). To me it would seem the rotational motion of the rotor is a very efficient way of achieving the high compression ratios required for diesel in air ignition. Surely by reducing the volume of the rotor recesses, compression ratios well inexcess of 20:1 could be achieved providing the necessary air temperatures (~900 deg) within the moving rotor chambers to achieve combustion upon injection of the diesel fuel (which would be injected in roughly the position of where the spark plug would be for a conventional gas rotary motor). I\'m guessing the problem lies with the rotor tips not putting up with the increased pressures during the compression cycle.

Any thoughts? :3Confused

[ds2000]

^ pretty much wrote exactly what I thought.

High compression, flakey tips :nono

That said, I\'d be interested to know what the RX-8 tips can copy with...

[ianelvar]

I remember reading a technical paper by a guy who was involved in early rotary development, which I\'ll try and rake out. If memory serves correct, there is some problem with attaining the high compression ratio that diesels need. I also have a feeling it was something to do with the shape and geometry of the combustion chamber that prevents higher compresion ratios, but I could be wrong there.

[banned advertiser]

I thought they were good, I guy commented to my brother about my RX7\'s and he said that his cement mixer had a rotor engined pump that has never let him down. I assumed they would be good as imersed in oil.

[Dominic]

Ian, I can see the epitrochoid geometry being the biggest problem as you suggest. With a piston engine, the piston rings are forced against the cylinder walls which are perpendicular (90 degrees) to the force of the piston rings providing the optimum sealing configuration for a high compression chamber. In a rotary engine, the "cylinder" (rotor housing) is at a constantly changing angle to the "piston rings" (apex seals), and during the point of maximum compression the apex seals are at their least optimum angle with the rotor housing to withstand high chamber pressures (see dodgy diagrams). I guess this is the geometry issue you described. I imagine it would require an alternative apex seal design to provide a greater contact pressure between the seal and the rotor housing.

[Ricco_04]

What is the compression ratio of the 13brew after you have put 0.8bar of boost through it? I know the Standard engine has a compression ratio of 9.0bar new.

There have been deisel engines developed - Rolls Royce had apparantely done one.

Deisel rotary engines are larger because to increase compression you need larger rotors & therefore housings to increase what they call "the \'k\' factor" but I cant remember off the top of my head what this is.

There are mentions of it in the History of the Rotary Engine book.

[Dominic]

What is the compression ratio of the 13brew after you have put 0.8bar of boost through it? I know the Standard engine has a compression ratio of 9.0bar new.

I thought turbo motors were lower compression than N/A?

Would be interesting to see a big Rolls Royce rotary engine. Think i\'ll do a search.

[Dominic]

Some pics of a Rolls Royce R6 Rotary Diesel Engine on

http://www.der-wankelmotor.de/Motoren/Rolls-Royce/rolls-royce.html

and a rather large rotor:2eek

http://www.der-wankelmotor.de/Motoren/Curtiss_Wright/curtiss_wright.html

[A7NTY]

Will a moderator please close this thread, this kind of discussion is \'dirty\' and wrong. Diesel should be kept to busses, trucks, trains and boats.

[Dominic]

Will a moderator please close this thread, this kind of discussion is \'dirty\' and wrong. Diesel should be kept to busses, trucks, trains and boats.

True LOL

But something tells me a diesel rotary wouldn\'t be quite so dull as a diesel piston engine :cool

Gotta wonder what it would sound like.

[shaunwil]

Will a moderator please close this thread, this kind of discussion is \'dirty\' and wrong. Diesel should be kept to busses, trucks, trains and boats.

And leman 24hr winning cars :spank :spank :spank :spank :spank

Shaun

[A7NTY]

And leman 24hr winning cars :spank :spank :spank :spank :spank

Shaun

That just proves if you chuck enough money at something it will win that car was a monstrosity - keep it pure - keep it petrol

[Martiny]

That just proves if you chuck enough money at something it will win that car was a monstrosity - keep it pure - keep it petrol

Apparently, you only need luck to win Le Mans

As for keeping it pure, that means ROTARY, and anything ROTARY is good. We should be removing the references to thos funny up and down engines !

:-)

[Ricco_04]

Will a moderator please close this thread, this kind of discussion is \'dirty\' and wrong. Diesel should be kept to busses, trucks, trains and boats.

:Giggle   Yeah, damm soot blowers - imagine our de-cat emissions! :o   (only joking, would be interesting to see & hear etc)

I would like to see a lot more done with gas fuels - sure that\'s where the future for our engine lie\'s (sp?)

[ianelvar]

I\'m suprised this isn\'t on the site, it\'s a really good read, especially for the technically minded.

http://varel.force9.co.uk:1133/RX7/RotaryEngineWhitePaper.pdf

The site may not be live 100% of the time, so I\'ll try to get it moved to a better place, but will have to do for now.