Mazda has been seriously working on the Renesis, with the known results aswell as some yet to be seen promises.
Looking at their hydrogen powerplant, one can only see the logic of this engine becoming the choice of the future. Gas (any kind of gas) will always be a more suitable powersource for Wankel engines then for piston engines. Since fuel gets ever more expensive, but also less and less accepted (emissions), the need for alternative powersources is big. So let's hope Mazda keeps the rotary alive.
Since they have now asked a homologation for the Japanese street use of the hydrogen prototyp (testwork) one can assume they are serious about this.
But there's more. It's often forgotten that other companies have been involved in Wankel-engines. One of them is Supertec, from Germany. One could say they are the genuine followers of Dr Felix Wankel.
Their new concept has been tested for a while, without a lot of publicity. Now they are ready to come out, big time.
An engine, capable of fuel consumption as low as modern TDI (diesel) engines, yet with all of the known Wankel advatages (low wheight, small, silent running,...) has been developed, and will hopefully be commercialised.
Check out the info (unfortuatly no pics or anything, but I have seen the pics myself, I guess they are still working on the site, as they always promised they wouldn't put it up until the engine was ready) here:
http://www.wankelsupertec.de
If this one can be produced for costs that are making it no more expensive then a common TDi it could really work out.
Expect more info soon (hopefully)...

 

very informative!

Would love to see some pics of it ,when they show them

Karis

 

Is this the same Supertec that was an F1 engine supplier several years ago?

 

No. the firm is called "wankelsupertec", and has been formed after a management buy-out at Wankel GMBH.

I know it's a pity there are no pics. Personally, I've seen some info, but for some reason they haven't (yet?) put it online.
The engine looks very much like any other KKM, with even peripheral ports (which really surprised me). It's not a "true" dieselengine, as it'll use a sort of sparkplug to ignite the mixture.
As all Wankel-engines it's small, and has a high power-output. As all Wankel-engines it's also almost vibriationfree, and able of high rpm's, and modular designed, meaning the relative ease of choosing for either 1-2-3-4 rotors will seriously sink production costs.
But unlike other Wankel engines, it is not thirsty. This could well mean the break-through of the engine, although a lot will depend on marketing budget. As we all know, poor marketing can make an excellent product fail, while good marketing can make a bad product sell.

 

how do I buy shares in the company!

If things go the way they should this will be very big!

 

Interessting!

/magnus

 

anymore info on this stuff?

 

The hybrid gas/hydrogen rotary that Mazda dropped into the Renesis was a bit of a joke in that the power output under hydrogen operation was very low. I suspect that in order to get more power out of the hydrogen unit they'd need a higher CR, which atleast with gas rotaries isn't all that possible. Any ideas regarding the CR of this company's hydrogen unit?

From the company's web page it sounds like they're also developing engines for "jet fuel" and diesel. They're using stratafied charges which makes it sound like they'll be taking off where Mercedes left off with direct injection. At the moment only Honda and VAG seem to be doing anything serious with stratafied charges. BTW: The new Audi A4's turbo 2.0L engine will have a 10.5:1 CR with this technology.

 

Reading the article in car and driver, I think they said it only lost like 20hp when on hydrogen IIRC. Just what I think I remember, so I am open to any proof otherwise.

 

I am going by what I saw at the Detoit autoshow and I seem to recall it was much more than 20hp. I'll see what I can dig up...

On the pure Hydrogen car from the 2003 Tokyo autoshow:
http://www.ultimatecarpage.com/frame...hp&carnum=1792
120hp/89ftlbs

 

you cant expect them to get high output #'s the first time around.
What does any V6 Hydrogen engine put out anyways?

 

WATER

 

it's not in english... ??

 

"WATER" come on!!
what a useless post.. heh

.....
"it's not in english... ??"
you cant speak Germaniese?

Click on the british flag in the upper left corner.

 

The compression ratio of a rotary is absolutely variable. A high-compression rotary will be physically larger with a shorter 'stroke' on the e-shaft. It would spin faster, but have more inherent mass. As the epitrohchoid shape gets fatter and larger, it gets closer to circular (rather than peanut) and the rotor face gets ever closer and the combustion chamber gets thinner and thinner. So yes, your compression ratio goes up. Besides, you can have lower recesses in the rotor face and not change the geometry at all.

Totally doable.

In fact, there was a 13A engine that Mazda used on a few FWD JDM cars that were the only engines Mazda made that deviated from the 12A / 13B geometries.

 

Thanks Crit after asking the question a number of times that's the first decent answer I've gotten regarding the topic. I've heard that the maximum CR of the current dimension of rotary is ~10.5:1 because beyond that a second flame front will occur. Any idea what CRs might be possible with a more round housing like the 13A?

 

Outside of Mazda and Sachs, not much time has been spent at all using different epitrochoid geometries. Nearly everyone that experiments with compression ratio uses the same cross-section as the production Mazdas and fills the rotor face somewhat in order to up the C.R. I have no idea what happens when you do that with respect to flame fronts, but certainly the R26B in the 787B and Kudzu Rolex cars had their third spark plug for a good reason - maybe that's why. I don't see why you can't start with either blanks, if somehow available from Mazda, or start with pre-93 rotors (cast recesses rather than machined), deposit weld material to them, then grind and polish until you get a flat face. Then you can do whatever you want from there. Anyone with a 3-axis or better CNC mill could do that work for you, given the proper part file.
Basically, they'll cut anything they can get an end mill (drill bit) into, with no regard for complexity of the shape. Hell, tear open someone's junked engine (or bid on a rotor/housing combo desk display from engines Atkins has blown up on ebay) and try it once. Fill, machine, see how it looks.

 

actually, Dr Felix Wankel and NSU did quite a lot of research on CR. Why does everyone seem to think Mazda more or less invented this engine??? The reason most Wankel engines ended up using a shape simular or close to what's used on 12A/13B is because it's the best compromise. By changing the excentric shaft, you can of course change CR, but this can only be done to a certain point where two things become a problem: the flamefront becoming very difficult to use/control due to a combustion chamber being too long, and second, the apex seals being too much "tilted" in relation to the housing. This would make the seals even more of a problem then now.
As for gas-powered rotaries: they have been build for ages now, with very good results, and mainly use LPG. We have several RX-7's and NSU Ro80's running around like this overhere in Europe. Actually, a Wankel engine is far superior when it comes down to gas. This is due to the fact that rotaries have a cold intake zone and a hot zone at the almost opposite side (combustion/ignition area) whereas the intake charge of a piston engine passes the valves which tend to glow and ignite the gas before it's supposed to do so.
The hydrogen engine has a future for sure, esp. since the Mazda engine is designed as a hybrid. This makes it possible to use normal fuel if required. And for highway use the 120hp would still be enough.
BTW: I finally have some pics of that diesel-Wankel, but they are a bit large, so I'll need to make them small enough to allow upload. I'm at work now, so it'll have to wait a bit.

 

sounds good.. can't wait till you post 'em up

 

How about the emissions of that diesel rotary? I know it's a pretty big problem amready with piston engines which is mainly solved by constantly improved catalysts, but rotary's are a bit known for this issue.

Or would the Renesis concept barge in here ?

 

I believe the 787B's R26 had a 10:1 CR, which to me seems quiet low for a Le Mans caliber engine.

rotary emotions: What is a reasonable maximum compression ratio by altering the dimensions?

I know that somewhere reasonably close to where I live is a FB with a propane powered turbo 12A. (I know someone who met the guy at a local drag strip)

Ultimately all fuel sources are energy mediums because more energy is required to extract/create/etc them then can be used by an engine. The maximum possible energy that can be extracted by typical gasoline is ~60% whereas diesel is ~70%. Hydrogen is a pipe dream because we don't have a good way to extract it and ultimately it is grossely energy inefficient. Unless nuclear fusion suddenly becomes viable I don't see hydrogen fuel becoming viable. At the moment Hydrogen doesn't appear to have a real advantage over electric vehicles and quiet possibly a disadvantage.

 

I have a book on the excentric dimensions and what's acceptable, but I must look that up.
The 26B LM engine uses "stock" (as in stock dimensions) 13B parts, so the difference in CR would only be in the rotor faces.
Obviously hydrogen is a difficult issue right now, but it sure ain't a pipe dream. Almost all bigger car companies are building prototypes, they wouldn't spend so much money on a concept that has no future. Several cars (BMW, Mazda,...) are nearly production ready, and several countries will start building hydrogen gas-stations to allow easier fill-up of the tanks during frther test fases.
The big problem with all electric and hydrogen cars is that they are not enviremental friendly as such: they pollute quite a bit. People tend to think just because they don't spit out fumes that these cars are clean, but only a solar powered (or human powered) car is clean. Hydrogen aswell as electricity is not readily available in nature and costs energy to produce. This results in what I call "remote polution". This has some advantages in areas that have many cars, but it's not a real long term sollution for the problems we are facing.

 

Electricity IS cleaner because as I said all fuels are energy mediums. Energy is consumed extracting/refining/transporting fuels, but a lesser amount cannot be extracted from the mediums. Less of the same energy could be consumed to make electricty. Hydrogen is the WORST offender of the "big" concepts that have been researched/looked at. As for spending money on technology that they felt had no future, how do you explain GM's massive investment in the Wankel and electric cars like the EV1?

...Anyway, if anyone has any other thoughts on rotary compression ratios I'd love to hear it.

 

ehh, GM is not a good example of well spend money, you're right.
But I'm not so sure about electricity being clean: unless you use nuclear power (which is the worst thing you could do because of the long term problems) making electricity is a very dirty thing: to make electricity you'll use plenty of fuel (either coal, oil, or gas) and you'll loose energy again when transporting and/or storing (battery). Even if electric motors are very efficient, powerplants aren't.
More intresting are fuels like vegetable oils, which can be grown almost everywhere, but so much would be needed we'll have serious problems to find enough space.

 

I believe to refine oil it requires a lot of direct electricity and I think burning of natural gas. It's the practically the same thing as producing electricity. Transmission losses and battery storage losses are minimal compared to the fact that you can't get anywhere close to the amount of energy out as is put in with gasoline.

I really like the idea of E85. It's 85% ethanol, 15% traditional gasoline. Regular gas engines need some minor changes (gaskets I guess) to be able to run E85. There are a number of vehicles that can run on either E85 or regular gas such as Chrysler's popular minivan. Apparently they've gotten it to the point where it's cost is similar to gasoline. One problem is that it doesn't contain as much energy so vehicles use more of it and make less power. I believe a bump in CR would help solve that problem. I'm not sure how well it would work if it powered all vehicles. I'm not a farmer, but apparently a certain amount of the prior year's crop must be kept so that there is soil/nutrients for the next year. Also, how much corn (or whatever) would be needed to power the world? Is it doable, or would it conflict too much with the food supply? I would imagine we could do it in North America, but could that supply places like Europe, China, Japan that don't have a lot of room to grow crops?