Ok, I hope you win, cuz I'm not doing a biuld till this one blows up

 

 

Coated rotors:





Note the "before" on the right side.

 

The benefits from thermal barriers in the combustion chamber are usually seen as across the board torque increases, as I understand it.

 

and HP too.

 

Absolutely not. Think of why engines get hot in the first place: they have fires burning in the cumbustion chambers. If the combustion heat can be better contained inside the combustion chamber than you not only get more power, you get a cooler engine. You do however get increased exahust temps; that's where the extra heat goes.

Anything you can do to make it harder for the combustion heat to "soak" into the motor itself will not only make engine power efficiency rise, but also result in better temperature control (in physics "efficiency" applies to the entire process. A perfectly efficient engine would make no heat, as the fuel energy would be turned into pure motion with no energy lost in the making of heat). Thermal barrier coated rotors would in fact run cooler because they are able to reject more of the combustion heat than they would uncoated.

 

DamonB is right.

 

I recently downloaded "Rotary Engine" by Kenichi Yamamoto...... AWESOME BOOK!!!!

Anyway, found this interesting tidbit on pg. 98:

 

this is a rotary?

 

Yah, I have no idea which one, though. Might be a 10a or something. You could probably interpret them as somewhat typical numbers, though. In the text it say that this was measured at the peak power A/F, and that as it was leaned out the "Heat of Unburned Exhaust Gas" was reduced while all the others increased.

Also, more tidbits not quite related:

Rotary friction owns teh piston!!!

 

And a breakdown of friction losses:



Man, those low friction, ceramic apex seals are looking better and better.....

 

I think you are refering to their proces of cutting the groves in the the inside of the rotor housings. So they give off heat better.



*sigh* .... thats what the coolant is there for. trying to preserve low coolant temperatures at the expense of the engine running to hot is stupid and pointless. Coating will keep the heat in the chamber rather then let it get absorbed in to engine parts, and as a result you will have more bang for the same amount of fuel/air, which is always good. It will keep the heat in the chamber that is burning the fuel/air also meaning it wont leak to others and cause detonation.

the only down side is hotter exaust and hotter coolant, but hey, what the **** do you want, a solution to make everything better? doesnt work like that. Preformance comes at a the cost in form of wear and tear. To put it simply though ceramic coating of the rotor faces does alot more good then bad, and hence its well worth it.



thats one good idea I must say. Radical since havent been really tryed yet... not that i know of, but sounds good. Goes right along my idea about using the compressor fromthe ac to make a phase change system with a jacket like the once for prossesors on computers but mount it on the radiator or ic. I will be writing a write up on that soon.

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hey batman, since you go this going right now you should try ceramic coating the apex seals, see how it goes. There is no way it will be worce then without so you cant loose ^^

 

Well, just have to comment in this. From reading the SAE paper Mazda released about the R26B LeMans motor, I seem to recall them ceramic coating... well, more or less everything. I don't have it on me to check right now, it's at home, but... yeah, seems to me there's more than a few benefits from this sort of thing.

 

i think you missed my point. the coolant/rotor housing temps are already a problem, why do something to make it worse? is longevity worth 5-6hp? hotter egts are a problem too, we already have problems keeping the turbine from melting on the track....

plus the oil cooler is 30% (or thereabouts) the size of the radiator, if they dont want heat going into the oil why do they have such a big cooler? i argee in a perfect world you dont want to use the oil for cooling, but we're living with mazda's design here.

have you tried this coating yourself? i would like to believe that some magic coating will give me all kinds or power and reliability and stuff, but i just am not seeing that. more power maybe, but we're not talking about a huge amount of power, that couldnt be gained elsewhere for less cost.

change my mind

 

I think you're looking at it backwards here. A lot of the oil cooler's cooling capacity is being used to shed heat transferred in from the combustion process. It's not ideal, but it's what Mazda has so they compensate for it. The thermal barrier coating would reduce that a bit, so in theory you could reduce the size of the oil cooler a bit. It wouldn't totally eliminate it, and you'd still have heating from friction so you wouldn't want to eliminate the oil cooler. Yes, you'd have to increase the size of the radiator to compensate. And the EGT issue is an issue for turbo people, and not one I claim to have the answer too.

Personally, I've had far more trouble with oil temperatures than water temperatures. I'm a 1st gen guy though, so.

 

i'm already running the largest radiator that will fit in the car, and its adequate. i do have an extra rotor though...

 

As far as Mikes comment about melting turbines while racing, couldn't a ceramic coating be used there too? Maybe even find some ceramic turbines?

 

Sort of related to this... I brought a brand new 12A PP... but unknown to me, the builder sprayed a heat paint in a variety of places to try and stop heat soak (or for some other reason that is only known to him?!?!?). Like around where the oil pump sits etc...

Anyway we installed the motor, fired up first pop, good oil pressure, compression... but after a short time of running it died. Checked all the externals, fine... so the next day cranked it up again and took it for a drive.... died. Towed back and stripped... the paint had come off through the action of the hot oil sloshing around and partially blocked the filter, ran all the bearings on the stationary gear / rotors and stuffed the eccentric shaft. The sump was full of silver grey flecks

Took the guy to Court and got most of my money back...

Not keen to put anything into my motor that Mr Mazda did not intend...

Saying that, I think that Isotropic finishing is worth a look for the eccentric shaft and some other areas...

http://www.xtremefinishing.com/

(lots of techo detail here of interest - all tested on rotary's). Part of Guru Motorsport that are rotary guys.

 

Batman at first when i read this thread it though it was kind of "i just want to coat my rotors in this **** casue it's good stuff" but i can now see you have read into a lot more than i thought, and i can now see why this would be an extremly effective method to increase output from the rotor and would love to hear more about how it turns out.

Anyway what really interests me is the two graphs that CypherNinja has posted the first one showing that rotaries have a much lower pressure friction (my guess would be the piston rings and thier surface area)

Althought he seconds graph shows that friction caused by the Apex seals. now it increases by nearly 400%, and i'm thinking it's becuse the seals are at the furtherest point from where the rotor is spinning, i can't do the calculations but i'm guessing at 5000rpm the seals would weigh nearly 50-100times thier non moving weight.

i would guess that the reason so much friction is caused is due to that your originally 50gram (or whatever weight not sure) seals are now equall to 5kg meaning that weight is being dragged over the housing surface causing A LOT of friction.

so if someone could work out the calulation of thier weigh when they are at 500rpm would be great.
Also what is the differnce (weight) between 2mm and 3mm seals.

as i'm guessing 2mm seals weigh less (duh) and this is the reason they last longer, ans so maybe we should look at making ligher (titanium etc..) seals instead of trying to coat current ones in whatever as it's the weight at high RPM thats killing the seals:

for example if we made seals the same strength at half the weight and the weight at 500rmp was 5kg then the new seals would only weigh 2.5 kg at 5000rpm which i belive will make a lot more difference than any coating.

 

mazda kinda did this with the renisis, the seals are shorter, and thus lighter.

the consesnsus here is that titanium wont work because it will gall. theres a thread about that every month or so

 

That chart above was for a 12A twin dizzy with 6mm apex seals

 

U underestimate the BATMAN

I have done my due diligence with regards to researching this topic.

At this point I am not looking into the friction coatings since abject application may result in the demise of the engine.

The thermal coatings that swain technologies and a few others that have done both rotors and pistons have had no ill effects when I conversed with them.

It would be logical to assume that if they had problems then word would have gotten out.

Second, they would have discontinued this service.

I like people to make sure that they understand the difference between some heat spray paint that u can buy at home depot and this process/product that I am discussing.

 

As far as titanium seals goes, you have to take into account the difference in absorbtion of heat. I don't know which buy titanium and aluminum definately have different rates, therefor one would get hotter quicker, you also have to consider their expansion rates under heat. Titanium may expand more or less than the stock carbon seals, which would require work to the epitrochoid to make it fit, plus if they expand a lot than you would have worse compression at lower heat levels, i.e. making it difficult to start. As far as ceramic coating seals, I've heard people wanting to do this for a while. One problem is that you have to find a ceramic that will bond to the certain metal of the seal, and you have to take into acount the change in size that the added ceramic coating will have. So you would have to trim your seals, so that they aren't too large, that or again mill out the housing. The other problem is that even though you may be able to find a ceramic that coats on your seals, you have to take into account how it reacts with aluminum. Plus ceramic coating seals will add weight. Therefor for now until someone finds a ceramic that will not add significant weight, that will bond to your specific seal, and will work with aluminum, the best bet is just to buy ceramic seals, which are lighter, stronger, and have a lower friction coeficent. I'm very interested in this. I will try and go talk to one of my proffessors and see if he knows of any materials that would work for the applications you have described batman, and that would not be overly expensive. I will also ask an aerospace professor of mine cause he used to work for nasa, and he may know of something that would work. This idea is a very good one, and I am very interested in what will come of it. And damon I have a question why is it that when you explain something, be it some complex thing that five people in the world understand, why is it that you always make it seem so easy? How do you make it so easy to understand the basics of fairly complex stuff?

- Steiner