Hey guys, Not sure if I'm posting in the right place but I was trying to decide where to post and this seemed like the only plausible area.
Well anyways, down to my point for those of you who looked at the title and are wondering what the hell DiesOtto is, the fast version is, an otto cycle engine run like a diesel cycle (a more in-depth description can be found here http://en.wikipedia.org/wiki/DiesOtto). It's a technology being developed by Mercedes right now and I was wondering what your guys thoughts about incorporating it into a rotary would be.

I don't know if anyone has ever thought about it before but I have been thinking about it. And if there were a way to set up direct injection into a rotary, with high compression to force the mixture to detonate like a diesel you would not only get more power but it would also decrease the emissions because you would have complete combustion of the air/fuel mixture all at once with out any left over fuel being thrown out the exhaust. Sure there are a ton of challenges still being faced to even get the DiesOtto working on a piston engine but it would be pretty sweet to see Mazda bring some sort of this technology and make it work on our rotaries so that we can not only have better emissions but also better fuel mileage.

The rotary engine would make for a relatively good candidate for a DiesOtto I think because it has relatively even temperatures throughout the combustion chamber which would help a more controllable pre-detonation take place.

I guess I just wanted to start this thread to spark some conversation with any person who has ever had any outlandish thoughts on how to or what ifs about the rotary engine.

So let me know what you guys think or if you have any other ideas that would make for some cool conversation.


And also constructive answers only please.

 

there is no info from your link

 

http://envirofuel.com.au/2008/03/08/...ine-explained/
that link should work

 

Ive done alot of studying in the dynamics of the rotary engine.
I think it would be a good idea to explore the possibility of direct injection or pre injection homogenous fuel/air mixed charges.

The FD sequential turbos setup is similiar in concept, in that it is designed to cover the full range of rpm at boost and personally i like the little power kick mid rpm range with the sequential setup of the FD over perhaps the variable vane geometry turbos mercedes is going to employ.

Something interesting though would be the mechanism of altering the compression ratio of the rotary... i wonder if instead you could accurately control the amount of intake charge in order to manipulate the pressures within into detonating **reliably** at the right time while under "cruising" conditions and then switching back to spark ignition under acceleration. Knowing the chaos that ensues from "bad" detonation id be incredibly hesitant thinking abt employing that technology on a rotary engine ...poor apex seals

just to start...

 

Just the kind of response i was looking for. thanks nemeii. And in thinking about it a possible way to accurately control the intake charge on a rotary might be a set up similar in style to the 6 port set up but only have the entire intake set up as a "valve" assembly similar to that with electronic actuators instead of vacuum actuators. And maybe while we are at it kick it up to at least 3mm apex seals

 

yea, id definitly say electronic flow controllers would be much more manageable.

Do you happen to have any pics of the 6port u were talking about?

heres a question...Diesel thruway shipping trucks are basically required to use turbo's nowadays to be able to pass emmissions. I believe the extra heat and pressure allow the pollutants to break down better so why couldnt they just apply this, add some turbo's and keep the *nice* porting from the 13 for the renesis haha - damni guess maybe its just wishful thinking.

I was reading the thread on the nrs ceramic seals and from the 30 freakin pages ive read and the results demonstrated id say they are definitely capable of handling the direct injection (true direct injection) in a moderately tuned car.

anyway I wonder if altering the shape of the rotor itself can lend a hand to better porting without creating absurd hot spots within the combustion chamber...would make for some interesting seal designs

 

Well I was referring to 6 ports that are on the 86-92 Gen 2 Non Turbo.
But obviously the 6 ports aren't set up to run the main intake ports so it would have to be designed to run all the ports not just the secondary ports.

And as for your question about just adding turbos to the Renesis that's a good question. I don't have the know how with turbos or emissions to really answer the question maybe somebody a little more tech savvy could answer that more completely. But a short response that doesnt explain anything would be that there have been turbos on gen 2 and 3 rx7s and their emissions still weren't that great so are we all that sure it would work?
And another thing from what I understand, those diesel 18 wheelers have turbos to help create higher pressures in the combustion chamber so that detonation can occur much easier. Most ANY diesel you see now-a-days has some sort of turbo system on it, from the 18 wheelers right down to the smallest mercedes or VW.

And playing with the shape of the rotor would be a pretty cool idea, I have been thinking for a long time if there would be some way to modify existing rotors in such a way that you could increase the compression. Like for instance if you were to increase the bore of the hole in the middle and put in a larger gear that would in theory increase the compression, it would make for alot of issues in terms of having to shave down the "points" on the rotor and what we would do about apex seals who knows. But that is a pretty good question nemeii maybe there is some way that the rotor could be shaped differently that would benefit this more than its standard shape.

 

^The upcoming Mazda 15X (or is it 16X) rotary will use direct port injection

 

Whats the mazda 15x somebody got a link to it?

 

I believe hes reffering to the 16x, its the new 1.6litre rotary engine, direct injection design. But if memory serves correctly its hydrogen powered?? can anybody confirm that?

Lol I believe all motors now-a-days besides the few *direct injection*
use "direct port injection".... Mr. "Beefhole"(I cant believe I just said) that but any way I'm assuming you meant direct injection?

And yes DaMaCCa you are right the 18wheelers are diesel direct injection. The higher the intake pressure and velocity, the better the low end torque and I would imagine the better the burn as more air makes for more diesel to burn more oomph per explosion.

DaMaCCa, Im not Sure what you meant by this:

Well I was referring to 6 ports that are on the 86-92 Gen 2 Non Turbo.
But obviously the 6 ports aren't set up to run the main intake ports so it would have to be designed to run all the ports not just the secondary ports.

---- got any pics to help describe???

Also when I was reffering to the shape I actually meant the flat surfaces of the rotor face of the combustion chamber perhaps be slightly slanted (pinwheel style) which would cause a centrifugal swirling effect that perhaps not only would cause a better fuel air mixture but also when a side port entered the chamber would essentially help force the combusted air out of the chamber and aid sucking in a new charge or better sealing without port overlap in a turbo application.

Your idea from what I understood of altering the center gearing size etc. to alter properties of the motor is more than feasible. I actually have calculations I can send you a couple pics of that demonstrate not only the different "stroke" and compression ratios but also the myriad of shapes that a rotary engine can utilize. Its pretty amazing really...and actually if i remember correctly you wouldnt need to alter the exterior shape of the rotor. However with the subtle compression ratio changes as far as the gas versions of rotaries were most likely to deal with you can have metal added to the rotor fac pocket and then reshaped to increase compression, guys on the forums have done this I believe.

As far as the turbo idea to help emissions... I figured the application of a turbo helped to bake and fulfill a few extra chemical reactions to pass cleaner burn emmissions. But like you said we've encountered that already on 2nd and 3rd gens so Idk, just something to think about seeing as how the porting is different on the new block and it seems the majority of speculation seems non-turbo oriented.

 

You can find info on the 16X on Mazdas website. They have diagrams and everything. By "direct port" I was referring to what mazda calls direct injection for the rotary engine. It's the equivalent to a piston engines direct port injection (fuel into the compression chamber via the head, not the manifold). They are putting a fuel injector almost on top of the housing, directly into the "compression stroke". I called it direct port. Maybe my terminology was wrong, but it's essentially the equivalent.

Mr Beefhole. I like that.

 

As a engineer working 4 Merc @ the engine developement department + a rotorhead privately, I have to tell you bad news.

This ain´t gonna work.

To make a long story short.

To have a direct injection is only the first (and smallest) step to that technology. So the 16X by Mazda has direct injection YES. But is it able to run a "roomingition metod"- NO
On the DiesOtto you phase / shift complete combustion timing compression ratio etc. to have a controlled knock.

+ What with all your force and power do you have to avoid on a rotary engine?
Yes...
now you know that there is alot to do before Rotaries get Diesottos (maybe it is impossible).
At least in my eyes it´s nearly impossible to get it reliable!

I hope that cleared things up!

Kind regards
Marc

 

well I see what your talking about after reviewing some animations of the new 16x.... Mr. Beefhole.
(its either that or Mr. Beefy, your call)

Essentially with the new 16x the fuel is jetted in pre-compression stage in order to chill the intake charge temps and help with fuel atomization. Which is where Marc's point comes in. There is no way (as of yet of course, which is where we come in) to effectively determine and control the point of "knock" (or detonation, ignition, etc.) of the intake charge. Without being able to do so accurately could lead to alot of cracked apex seals (yes, even the silicon nitride ones) not to mention a really crappy idle ;p

What I was thinking and didn't realize I hadn't precisely described apparently was either:
A) Creating a sealed cavity that is volumetrically variable and when in the rotor reaches the correct position (generally where spark plugs would ignite the charge) the cavity reduces its volume which exhumes the air within into the already compressed combustion chamber thus pushing the temperature up that extra little bit enough to ignite the mixture. Essentially controlling air volume and pressure I dare say in a moderately accurate fashion if conditions are set based on the intake charge temperature and velocity.

B) This one is somewhat speculative as I don't have any evidence of it being possible...Creating an injector that is heat insulated, and strong enough to allow gasoline to be directly injected into an already compressed combustion chamber thats air content is hot enough to self ignite the fuel spray. In retrospect I dont have the slightest idea what the peculiar properties of the fuel burning pattern would be as I think it effectively would have a flame thrower effect inside the combustion chamber so idk how thoroughly and clean it would exaust.

C) Another method I have devised in quite some detail but as of yet I'm not comfortable revealing it as I believe its quite realistic and could possibly be scavenged by someone of greater means ad be effectively stolen from me without credit given. VPTs-R


DaMaCCa, what are your thoughts on this too??

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~
Woeep (Marc) this is for you, maybe it will help ya out:

gut sehe ich, was Ihr Sprechen nach der Überprüfung einiger Animationen des neuen 16x…. Herr Beefhole. (sein irgendein das oder Herr Beefy, Ihr Anruf)

Im Wesentlichen mit dem neuen 16x wird der Kraftstoff im Vorkompressionstadium gespritzt, um die Einlassgebühr Temps zu kühlen und bei der Kraftstoffatomisierung zu helfen. Welches wo Marc' ist; s-Punkt kommt herein. Es gibt keine Weise (ab dennoch selbstverständlich, das ist, wo wir hereinkommen), den Punkt von " effektiv festzustellen und zu steuern; knock" (oder Detonation, Zündung, etc.) von der Einlassgebühr. Ohne in der Lage zu sein könnte zu tun zu viele gebrochenen Spitzendichtungen (ja, sogar das Silikonnitrid eine) ganz zu schweigen von einem wirklich crappy Leerlauf so genau führen; p

Was ich dachte und didn' t verwirklichen I hadn' t, das genau anscheinend beschrieben wurde, war irgendein:
A) Das Herstellen eines Siegelraums, der volumetrisch Variable ist und wenn im Rotor erreicht die richtige Position (im Allgemeinen, wo Funkenstecker die Gebühr anzünden würden), das der Raum sein Volumen verringert, das die Luft innen in die bereits komprimierte Verbrennungskammer exhumiert, welche folglich die Temperatur diese kleine Extraspitze genug hochdrückt, um die Mischung anzuzünden. Im Wesentlichen steuernluftvolumen und Druck traue mich ich sage auf eine gemäßigt genaue Art und Weise, wenn die Bedingungen basiert auf der Einlassgebührentemperatur und -geschwindigkeit gesetztes sind.

B) Dieses ist als I don' ein wenig spekulativ; t haben jeden möglichen Beweis von ihm seiend möglich…, einen Injektor herstellend, der die isolierte Hitze ist, und stark genug zu erlauben, dass Benzin direkt in eine bereits komprimierte Verbrennungskammer, die ist, Luftinhalt ist heiß genug zum Selbst anzünden den Kraftstoffspray eingespritzt wird. Im Rückblick habe ich nicht die geringfügigste Idee, was die eigenartigen Eigenschaften des brennenden Musters des Kraftstoffs sein würden, wie ich denke, dass es effektiv einen Flammenwerfereffekt innerhalb des Verbrennungskammer so idk haben würde, wie gänzlich und sauber es exaust wurde.

C) Eine andere Methode, die ich in durchaus irgendeinem Detail aber ab dennoch in I' geplant habe; m, das nicht bequem ist, sie aufdeckend, da ich sein ziemlich realistisches glaube und durch jemand der größeren Mittelanzeige vielleicht gereinigt werden könnte, wird effektiv von mir ohne die gegebene Gutschrift gestohlen. VPTs-R

DaMaCCa, was sind Ihre Gedanken auf diesem??

 

whats up guys no response?

 

Hey Nemeii,
was my english that terrible that you thought you have to translate it for me??

And to be honest... Your english text was more understandable to me as the google translated germenglish

About your Point B.
One of the biggest problems of the Rotary engine in matters of fuel consumption and emissions is the thermodynamical disadvantage of the thin long combustion chamber.
A direct injection of the fuel which would probably work, you just have to calculate. (Direct injection fuel pressure is @ 200bar.)
BUT the problem you´ll have will be that you can not fill the long thin chamber homogenously with fuel.
Even when you can condition all factors, to have a self burning mixture @ the point you are injecting the fuel. This won´t be a efficient combustion!
There are a few facts why.
1. No homogenous mixture
2. your told flamethrow effect (no controlled burning)
3. Extremely different temperatures in the combustion chamber

So the power you are getting out of the combustion is poor + The emissions due to high temperatures (NOx) are also bad
+ When you developed a combustion geometry + maybe three injectors per chamber for homogenous mixture, You have the biggest problem of all.

You cannot pre define a system to have a knock all the time at the same point (angle).
Because all your parameters change!
Number of revolutions (timing) / pre tempoerature of the Combustion chamber / fuel Temperature / Air Temperature etc.
Therefor you need a controllable system where you can change the angle of the self ingnition (compression controller). And this is in my opinion impossible for a rotary engine in a costumer car!
Maybe you could build a system where you can phase the angle of everey rotor itself via a extremely complicated and electric controllable eccentric shaft!
but I don´t know who... but I wont pay extra 5000$ for that engine (which will not be as reliable as a "simple" eccentric shaft).. And I don´t think that if you are mazda or any other OEM, you would build a not reliable (or critical) engine?!

So, you see...
if you are smart, there are alot of possibilities to create patents.
But I´ll bet, that they will be never used!

If I´m wrong, the Mazda engineers will get the greatest respect!

I hope that helped ;-)

kind regards
Marc

 

lol, no not at all. I thought your english was fine I just thought it might be easier for you to read if it was already in....germenglish provided by babelfish =P Sorry, no offense was intended.

Thank you for clarifying some points for me and confirming some suspicions I had as to the actual physics of the combustion reaction. Does this mean the more spherical (or closer to spherical) the combustion chamber the more efficient the combustion?

Also I you didnt mention your opinion of example A. In that case the intake charge of air i was tossing over the idea of having perfect premix of air/gas entering through the intake instead of injector squirts and relying on spray pattern? Granted if trhe intake manifold detonated for whatever reason it probably wouldnt be a good scene, would it still be possible?

Thanks again for talking, not to many people care to talk theory.

Where is DaMaCCa??

 

well so much for this thread....::sigh::

 

Hey guys sorry I haven't been around between trying to keep the car running, school, and work it has been a bit hectic. Very Hectic. So I come to you on the eve of Thanksgiving here in the States with a possible proposed location for a direct injection injector location. It seems like it might work to me because it could spray through the whole length of the injection chamber perhaps? Right at or milliseconds before complete compression is reached.

Forgive my some what hodge-podged image doing the best I can with what I got.

The injector is at the top of the rotor, the part that isn't labeled.


as always let me know what you think

 

ohh and Nemeii the 6 port motor I keep referring to is the U.S. rotary motor that came in the 1986-1991(2) Non turbo cars. It was also found in the 84-85 gsl-se. It ran primarily on 4 ports until it reached the upper rpm range in which case a rotating "valve" would open up a 5th and 6th port to allow for greater power and more airflow in the higher rpm range. It would be comparable to Variable Valve Timing on a Reciprocating Engine, it's not the same but similar in idea.

My idea was that if you could incorporate that same style "valve" from that motor but for all intake ports with electronic actuators so the ECU could have control over whether or not the intake port was open or closed, and how far open/closed. The "valve" would obviously be shaped better than the original ones from the 13b motor, perhaps something that resembled those same ports with PineappleRacing inserts?


A few images of both the inserts and "valves" or sleeves can be found here, along with an image of the intake set up where the "valve" opens/closes on the 13b motor from the years I mentioned. http://www.pineappleracing.com/index...PROD&ProdID=11

 

did i kill this thread or are you guys just busy from the holiday weekend?