brillo

the quasiturbine is back!

http://auto.howstuffworks.com/quasiturbine.htm

rotarygod

Does anyone besides me have a problem with the combustion chamber shape as it goes through it's different phases?

BlueEyes

what's the problem you see with it? I don't really know how compression ignition chambers work, so I can't really comment.

EDIT: Are you concerned about the one with carriages?

guy321

It doesn't seem that the combustion would rotate the doohickie properly?

Rhawb

It looks like a rotary with a square instead of a triangle...This took them years to come up with? :p

army_rx8

i'm guessing he ment teh one with the carriages..that was a lill odd...i didn't really see how the chambers was sealed..looked liek it would be to viable to me...the one without was just our engine with one more face to it.

army_rx8

but both seem to have a lot more moving parts then our engine

guy321

how would it get a good seal

army_rx8

i can't see how the one with carriages could get a good seal...adn i'm not even too sure how the one with out could either...it seems that the two parts combine right where it would seal...so you can't put in an apex seal liek we have b/c the "joint" seems to move slightly as it rotates...so i'm not too sure haha the article in how stuff works isn't in depth enough to talk about sealing issues

Rotarian_SC

Seems like you could make one with a larger displacement than the 13B and not have to worry about the flame front for the spark plugs, but I seriously doubt that this will make its way into any mass produced vehicle. They would just go with the more proven Rotary instead I would think.

army_rx8

indeed.......no one will touch this....and mazda will stay with the wankel b/c it is proven and tehy are set up to manufacture it already

brillo

it likely has non auto applications first, as the risk and cost are less. While it has more parts for sure than our wankel, its still a ton less than a piston engine. I'd love to see the techincal white paper on this.

army_rx8

^true true. it would be nice to see. but i think this is going to be an engineering fad...that pops up every few years

T.T.

Wow...this engine seems superior in every way. I would definitely want to see an automotive application of this. The only advantage the rotary seems to have would be maintenance because of less parts.

army_rx8

hmm this has poped up on teh web every now and again since teh late 90's.....i think someone one time mentioned that it was in a go kart or soemthign like that....but that's teh only working model i've ever herd of (but haven't seen). it would be nice......but being on paper..and in a real world application are two totaly different things. oh well guess time will tell.

m477

Nice, but I'm not giving up my two Doritos on a stick! :p

Seriously though, I think it would be cool if Mazda or somebody spent sometime researching the possiblities of getting this engine in a production vehicle.

MassiveAttack

This thing would have so much rotating mass at the perimeter I'd wonder how it could ever run efficiently. Not to mention that the bizzarely shaped combustion chamber with carriages can't possibly leave fewer unburned hydrocarbons than the Wankel. I mean, how is the flame front going to get into some of those corners effectively? Might be a great motor for light applications, but I don't see it ever making it into an automobile.

--Massive

Apophis

I agree... it seems pretty freakin ingenious to me...

Right, but the late 90's was 6 years ago... the conventional ICE has been around for over 100 years. The patent for this engine hasn't even been out for a decade. Give it time...




It seems that the goal here is photocombustion, i.e. pressure-induced combustion... meaning you don't need to ignite it like in a piston or rotary... it will ignite itself due to the extremely high pressure, much like a diesel. Assuming a homogeneous fuel-air mixture, it should ignite uniformly throughout the (oddly-shaped) chamber. This isn't possible with the rotary because the combustion chambers simply can't compress enough.

It seems like this is almost like a diesel version of a rotary! More torque, & more fuel efficient... and can you imgaine if they got this thing to run without oil? The mechanical parts are nearly perfectly balanced at all times which could mean that the QT could be so smooth as to make our rotary feel like... a piston engine! :p I'm really impressed. The fact that they got one to work in a go-kart shows a ton of promise in my opinion. It really does seem that the biggest disadvantage of this engine is the lack of testing to date.

MassiveAttack

I certainly understand the photocombustion, but there's still got to be a place where the flame front(s) will start. All those nooks and crannies and pointy spots will not be uniform in they way they heat. Therefore some area will be hotter than another and photocombustion will begin there because the heat in that area will be higher.

And, other than that possible Go-Kart demonstration, I don't see anything that indicates they have a production-ready internal combustion version ready. Not even for the basic (non-carrier) quasiturbine. Not to mention that this will have many more moving parts than the current rotaries, and the long-term durability of these items in a IC engine is completely untested.

On the positives, I like the idea that this thing would have virtually no vibration. Can't argue with that. Very little oil? I'm in.

Apophis

Well, i think the thing is that if it's a homogenous mixture, it should all be able to combust. Would there be a place where the flame front starts? I dunno... if it's a gas, all pressure should be equal, right?

Anyway, check out

http://www.quasiturbine.com/

Pretty interesting... again, given that it's only been a few years I think things are progressing... you can have them make you a QT engine...

army_rx8

hmm thanks for the link :D

MassiveAttack

Looks like the only quasiturbines for sale are pneumatic. Not that I would downplay THAT accomplishment, but it's far from a working IC version. Someone is probably closer to making a Stirling automobile engine... Advantage: dead quiet.

Rotarian_SC

Well there is a version without the carriages that I was talking about that I don't think would have the flame front problem. It basically looks like a Wankel except with a square and oval.

globi

The whole article seems to mix up the so called quasiturbine with the so called HCCI engine.
Both can be looked at seperately and I would definitely argue that the HCCI concept would be easier to get to work on a piston engine than on any other engine concept. A piston can be sealed easily. A piston can be cooled easily and a combustion chamber of a piston engine can be sealed and cooled easily. Also a piston engine with a long stroke can have an extremely high compression ratio, definitely higher than that of a quasiturbine. In addition a piston engine can fall back on 100 years of R&D.
So my very first question would be, why are there no HCCI piston engines in stores?

And if the quasiturbine was operated as a gasoline or diesel engine I see plenty of disadvantages over the piston engine or the rotary engine:
* More moving parts are exposed to hot combustion gases (that need to be sealed, lubricated and cooled at the same time).
* The combustion chamber has an extremely high surface to volume ratio (= efficiency killer).
* The engine appears to take more volume than a rotary engine (= more weight).
* The rotor is difficult to cool. Even if the rotor is made out of unobtanium and can cope with the heat you still need to deal with detonation.
* The clefty combustion chamber is also more prone to detonation.
* Given the large circumference of the engine the centrifugal forces on the seals would be pretty high at higher rpms.

Last but not least, Felix Wankel actually patented a rotary compound engine with a triangle rotor to supercharge 2 square shaped rotors with double expansion (more expansion ratio = higher efficiency). It obviously never made it into production, but if I had to invest into an engine concept with square shaped rotors I would favor this over the quasiturbine. US patent: 3,993,029 (1976)
The difference between the quasiturbine and the square shaped rotor is mainly that the quasiturbine appears to be a true rotary engine (rotor revolves around a fixed point) but it has more moving parts that are exposed to hot combustion gases which is never favorable.