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robk
10-13-2005, 10:15 AM
Hello,

Mostly I lurk; picking up useful information at times for my home shop. Thanks to all that post for the information you have imparted.

Have any of you heard about this engine called the Quasiturbine? Although it has been around since 1999 I stumbled onto it through this web site: www.howstuffworks.com (http://www.howstuffworks.com) and then www.quasiturbine.com. (http://www.quasiturbine.com.) Is this the next "100 mpg" carburetor that gets shelved? In my searching I have found papers that seem to be sponsored by the by the design/inventor that tout all the wonderful things the engine does. And why would they not? It all sounds good. Almost to good.

I have not been able to find any information about the downside or problems with the engine. Think about the applications and the simplicity of systems that require an engine if this engine is viable.

Perhaps I could go back to working on my own vehicles with an engine this simple.

By the way, I have no affiliations or ties with the Quasiturbine people. I am just a humble architect, marginal welder, and really bad machinist with an inquiring mind.

If this has been discussed before my apologies. The search function turn up no results.

Rob

Forrest Addy
10-13-2005, 10:50 AM
"I have not been able to find any information about the downside or problems with the engine. Think about the applications and the simplicity of systems that require an engine if this engine is viable."

Well, how about all those close fitting parts moving in hot gas? I recall seeing over the years dozens of very clever engine designs that failed to make it to market because of complexity, sealing, etc. These are not trivial problems to be glossed over with dismissive remarks but serious flaws that profoundly affect the cost of manfuiacture and the thermodynamic efficiency of the engine.

The Wankel engine showed as much promise as any but only Mazda had the gumption to invest in it and bring a car designed for it to market. The car was the RX-7. Mazda spent hundreds of millions and never made a profit on the design. The car while reliable and a real performer had lackluster fuel economy.

So it's not because of the Big Guys protecting their investments that necessariy causes new engine designs to be largely ignored but the practical questions like: Will it really work? Is it economical to manufacture? Will the public accept it? And, the big one: Can we make a profit on it?

Spin Doctor
10-13-2005, 11:13 AM
<font face="Verdana, Arial" size="2">Originally posted by Forrest Addy:
Can we make a profit on it? </font>

That sums it up perfectly

robk
10-13-2005, 11:17 AM
Good points about the hot gasses and potential expansion of parts. Solvable problems? Who knows.

In the limited info I have seen the only things powered by this engine are a chainsaw and a go-cart. Both of those use compressed air as the motivating force. I have yet to see a self sustaining engine powered by fossil fuels.

This engine appears to be the next evolution of the wankle; solving the downfall of the poor fuel economy.

Rob

Evan
10-13-2005, 11:32 AM
Forrest,

I believe the first Mazda wankel sold in North America was the RX-2. I drove one in the early 70's. It was a little firebreather, weighing just around 2000 lbs with 130 hp. They had constant problems with tip seals on the rotors but were otherwise pretty reliable.

Rustybolt
10-13-2005, 01:25 PM
If I remember right. The Wankle was originally intended as an air compressor for aircraft.
And so far, from what I can see on their website, they have a four vane air compressor.

Perhaps if they used ceramics for an internal combustion version.

I wish them luck.

Wirecutter
10-13-2005, 01:37 PM
The quasiturbine seems interesting, but I think it's a little silly to claim they can extract power without a crankshaft. Of course it has a crank, they just call it something else. An output shaft by any other name... Oh, I suppose you could use it to generate heat and extract that.

I always thought the Wankel was a nifty engine, but I have also heard that:

1. Apex seals are a bear to get right and reliable.

2. Wankels generate a lot of heat.

I always thought that one reason the Wankel is not as fuel efficient is that the power is extracted from a "glancing blow", rather than the "dead on" configuration of a piston engine. The quasiturbine works the same way, from what I can see. The quasi also has seals analogous to the Wankel's apex seals, but they have to move in and out a lot as the rotor spins. Are a Wankel's apex seals stationary with respect to the rotor? That would make them a little more simple.

Another thing to consider is that, like a Wankel, the quasi is going to generate a lot of localized heat. The "hot" area is in the upper left of the engine as shown in the diagrams. Seems like that will be something that has to be addressed.

One cool thing is that the Wankel and the quasi can run on a variety of fuels. This feature is one reason the US military has used Wankels for generators - they can burn most things you can pump.
Finally, it looks like the quasi concept could be an interesting way to make a compressor, for either shop air or for refridgeration.

Evan
10-13-2005, 01:42 PM
The Wankel rotor seals are mounted in slots in the rotor apex and are held against the housing by centrifugal force as it spins. They are free to slide in and out.

Ausserdog
10-13-2005, 02:14 PM
Mazda wasn't the only one to sell Wankel engines in vehicles. I'm pretty sure that they bought the rights from NSU after their Wankel powered car didn't catch on too well. My brother had an RX-3 that we did a tranny swap on. He let me drive it after we finished it. That thing was FAST. Only problem was it badly needed a brake job. Didn't find that out until we were coming up to a blind, off camber corner going way too fast....

Sometime in the mid to late 70's Suzuki had a street bike with a Wankel in it - supposed to be the equivalent of a conventional 400-500cc engine.

Don't remember who made it, but someone had a "utility" engine (like a Briggs & Straton) too.

Tom

robk
10-13-2005, 02:17 PM
The quasiturbine web site showed pictures of this engine mounted in a compact car but no video of the car moving under its own power.

What I found intriguing about the set up was that the shaft to an output device, i.e. generator, transmission, pump etc., could slide through the middle of the engine.

The site also talked about a propeller, possibly an impeller, being fitted to the center of the engine for whatever your imagination would want to do with that setup.

If more horsepower were required would a second or third engine assembly be fitted on a shaft.

Interesting concept for an alternative to the piston engine.

I think I will wait until the price comes down a little on the educational model before getting one to fool with.

Rob

SGW
10-13-2005, 02:23 PM
Is there any evidence that one of the things has ever actually RUN as a combustion engine? All I could find, skimming the website, was a lot of, "This is how it would work if it did," but I might have missed it.

aboard_epsilon
10-13-2005, 02:33 PM
Hey dont forget us Brits


http://homepage.ntlworld.com/derek.nicol/

all the best...mark

jburstein
10-13-2005, 02:40 PM
"1. Apex seals are a bear to get right and reliable.

2. Wankels generate a lot of heat.

I always thought that one reason the Wankel is not as fuel efficient is that the power is extracted from a "glancing blow", rather than the "dead on" configuration of a piston engine."

Actually the real reason for the lack of fuel efficiency are the two problems you mentioned. The Wankel does run hot (I believe because it vents the exhaust much later than a piston engine does), and the apex seals are somewhat fragile. Combine these two and you have an engine in which pre-detonation is both likely (because of the fragile heat) and very damaging (because of the apex seals).

The solution is to make the engine both run a little cooler and less likely to detonate by richening the fuel mixture (read-waste fuel).

Any difference in efficiency because of the "glancing blow" is made up for by the elimination of the huge amount of reciprocating mass inherent in the piston engine's design. Also efficiency is gained by holding the exhaust gases longer; piston engines vent them long before they're done expanding, wasting the energy that could be gained. Wankel engines hold them longer, and use that energy, albeit at a tradeoff of running hotter.

Disclaimer: This is my understanding, but I'm not an expert, so I'm sure something I said is wrong, or misstated somehow, hopefully someone will correct it though.

-Justin

[This message has been edited by jburstein (edited 10-13-2005).]

Wirecutter
10-13-2005, 05:11 PM
<font face="Verdana, Arial" size="2">Originally posted by aboard_epsilon:
Hey dont forget us Brits


http://homepage.ntlworld.com/derek.nicol/

all the best...mark</font>

Now that's cool. Those things must be ridiculously fast. Well, most of them are racing bikes, after all.

Wirecutter
10-13-2005, 05:14 PM
<font face="Verdana, Arial" size="2">Originally posted by jburstein:
Also efficiency is gained by holding the exhaust gases longer; piston engines vent them long before they're done expanding, wasting the energy that could be gained. Wankel engines hold them longer, and use that energy, albeit at a tradeoff of running hotter.</font>

I have to ask the obvious question, then. Has anyone investigated a way to retain the exhaust gasses longer in a piston engine? Or does that screw up everything else?

Evan
10-13-2005, 05:17 PM
That is basically what a turbocharger does. It extracts more energy from the exhaust.

gkman11
10-13-2005, 05:30 PM
A longer stroke would do it also but designers with $$$ budgets and everything to gain by achieving higher effiency don't. Must be a good reason.

gunsmith
10-13-2005, 06:24 PM
I don't think the engine efficiency is the problem. Were we fall down is the drive line. So much energy is lost in the transfer from the engine to the road. Solve that almost 45% loss and we could reduce our engine output and thereby increase fuel efficeincy.

Flash319
10-13-2005, 06:55 PM
Evan,
A turbocharger does not extract energy from the engine unless it is connected to some other device that does work. All a turbo does, in most cases, is help force more air into the engine thus more fuel can be burned. The only efficiency gain is that you eliminate the energy wasted trying to draw the air into the cylinders. You have a positive pressure forcing the air in instead of a vacuum.

Evan
10-13-2005, 07:22 PM
If a turbocharger doesn't extract energy from the engine then just what makes it spin???

It uses waste energy in the exhaust gasses to pump more mixture into the cylinders thereby increasing the volumetric efficiency of the engine and also increasing the volume of exhaust making it spin and pump even more.

Flash319
10-13-2005, 09:44 PM
If a turbocharger doesn't extract energy from the engine then just what makes it spin???

I misunderstood the point you were making.

Sorry, yes it does extract energy from the engine, but only provides a means to burn more fuel not make the engine more efficient. Volumetric efficiency is just that, the efficiency of how you fill the volume. Yes you gain some efficiency up to the point at which you start making boost pressure. If the intake is at atmospheric pressure then you are not using any energy moving air. This does not mean you get more energy for the same amount of fuel burned. You get more Hp but you use more fuel.

I was thinking about the energy that internal combustion engines waste. Something like 30% of the energy from gasoline goes into making power, the rest heat. It has been like this for like 50 years. Nice progress eh!! Damn I hate cars and the archaic companies that build them.

ibewgypsie
10-13-2005, 09:51 PM
Turbochargers extract heat and inertia from the exiting exhaust gases. THEY do produce more backpressure but make up for it in chamber pressure with the boost.

They also transmit lots of underhood heat to the incoming air mixtures, hence the intercoolers used a lot on the production-fast cars.

A turbocharger motor has "lag time" if sized correctly it is nearly irrevelant. A supercharged engine has power on tap, very little lag time. I love the whine of a blower. Newer blowers are actually more efficient than the old lobe'd type 6-71s but lack the same thrill.

In the 70s I put two Rajay turbochargers on a big MonteCarlo w/4 speed. I could not get all the spark rattle out of it, even with water injection and retarding the timing. It'd come on when it did like a 2 stroke bike with pipe (all at once). Now the Road Runner w 440 6-71 blower and two dominators, it was UNREAL.. I'd have to crank it with a joy bottle of gasoline spraying into the carbs to get it to fire off.. after it was warm it'd crank.. He'd drag it down the shop back then and I'd fire it up and he'd ride around Chattanooga looking for people to embarrass. It wore out and blowed-out a brand new set of tires from The Texaco in Rossville in less than 150 feet. (on a bet).

Wankels are "fast".. One blowed blue smoke on my old built harley as it showed it's tail lights in the distance. He downshifted and left me I was running about 130 or so. (by tach) He had his toy built right. I think it had nitrous.

I happen to have two smallish turbos off a mitisubishi pair of cars I junked out. One is good other the bearings are crap.

A diesel turbocharger needs no oil pressure bearings seals since it produces no real manifold vacuum, put one of them on a gas burner and you have instant oil smoke. (*don't ask)

[This message has been edited by ibewgypsie (edited 10-13-2005).]

PSD KEN
10-13-2005, 10:13 PM
The air is heated by compression, ergo intercoolers.
Diesel turbos most assuredly require oil seals, as they are lubed by engine oil pressure.
Bad seals will result in copious amounts of oil sucked up and ingested by the engine

darryl
10-14-2005, 12:43 AM
To whomever asked, yes a piston engine can be made to utilize the pressure of burning fuel more appropriately, but not by using a conventional crankshaft. There is an optimum speed for the piston for every part of each burn. If it can accellerate quickly from the point of ignition, then continue travelling down the cylinder at a speed which adds an even torgue to the output shaft, with this movement continuing until most all the fuel is burned, then can quickly come back to tdc and travel downwards again at a speed which inhales the most fuel/air mixture, then can travel upwards in a speed pattern which results in the least shaft energy being expelled to compress that mixture--it can extract more energy from the fuel than can be done using a crankshaft. I've never yet seen a design that does this without being somewhat rickety. There have been cam and roller designs, spiral groove designs, etc, but none have the solidity of the age-old piston/connecting rod/crankshaft design.

Profit is a powerful motivator. Any significant increase in economy to the consumer, combined with an increased cost to the manufacturer- not going to happen. Standard piston engines are going to be stuffed down our throats until half the lava in the earth's core is suddenly ejected to form a new moon. ( a blue one, probably)

J Tiers
10-14-2005, 01:07 AM
I have a kohler engine that I got from the estate of a guy who was evidently trying the piston speed thing.

I replaced his funky piston and rod that had a sort of cam action to it that seemed to be trying to adjust the piston speed near TDC.

He was using that Eclipse generator I posted a pic of as a load to determine power output...... I got some of his notes as well, but I have no idea what they mean, they are far from clear. They sure don't clarify what he was up to.

Evan
10-14-2005, 01:49 AM
Flash,

A turbo does increase the thermal efficiency of the engine a small amount. Carnot efficiency depends on the temperature difference between the hot and the cold side of the engine. A turbocharged engine is running hotter so there is a greater temperature drop plus some of that energy is captured by the turbine. This is largely offset unfortunately by the fact that heat is wasted as the square of the temperature.

Diesel is a lot more efficient than Otto cycle and that giant ship diesel that has been posted here from time to time can exceed 50% thermal efficiency.

The problem with heat engines is that they can never even reach never mind exceed the Carnot efficiency which is about 61% of fuel heat converted to motion.

SJorgensen
10-14-2005, 02:26 AM
Turbo's and superchargers boost the intake manifold pressure. This is useful when you need more air and fuel than atmospheric pressure at your altitude will allow at full throttle.

We almost always are not in that situation. Our engines are "throttled" and not boosted.

My Brother had an RX4 and it was a small cheap boxy car. He got it to 135mph and scared himself ****less. Later he and my father owned RX7s. These were not very fuel efficient nor dependable machines. They were nice in lots of ways, but an engine innovation SHOULD EXCEED the performance of the prior technology. If it doesn't it should be considered a failure.



[This message has been edited by SJorgensen (edited 10-14-2005).]

DICKEYBIRD
10-14-2005, 08:41 AM
Just to fill out the Wankel story a little, the NSU Wankel Spider and twin-rotor R080 pre-dated the Mazda Wankels by a few years. They were sold here in the states back in the middle to late 60's. NSU vehicles were quite inovative but the company was gobbled up by Audi.

Mazda vastly improved the rotor tip seals which made the engine a more viable power source.

As mentioned before, Wankels did produce a lot of heat and NOISE! Ain't nuthin' louder than a racing Wankel with a tuned exhaust!

topct
10-14-2005, 09:34 AM
The latest thing going for the internal combustion engine is variable lift and timing of the valves.

Changing the timing and ratio of the piston/crank assembly has been tried, but as Darrel says they are not dependable.

Just changing when and how much the exhaust valve opens has helped raise the thermal efficiancy and thus fuel milage and power.

When the hydraulics or electronic means of valve operation are combined with a modern engine managment system the engine can litteraly be totally tuned on the fly. I'm not sure, but I think there might be a couple of F1 engines that use either hydraulic or electronic valve actuation.

This is the problem with the wankel. It is pretty much stuck with it's timing. There is no way to mechanically change it as speeds and loads change.

Another thing that has and is being looked at is a constant speed engine. Bore and stroke can be optimized for a set rpm, and by electronically varying injection, and valve timing depending on load and not engine speed the engine can operate within a much smaller rpm envelope of efficiancy.

This will only work with a constantly variable transmission however, and there comes the problem of drive train efficiancy.

I think Toyota is using some kind of variable ratio trans in one of there high mailage cars to keep the engine in it's "sweet spot".

As far as the Quasiturbine, it too would suffer the exact same problems as the wankel. That's if it really operated as an engine.

------------------
Gene

[This message has been edited by topct (edited 10-14-2005).]

Ron LaDow
10-14-2005, 11:13 AM
I didn't see this mentioned:
Problem with the Wankel (and the quasiturbine) are the corners. Flame won't spread into corners, since the surface area of the (relatively) cool metal quenches it.
The result is inefficency and dirty exhaust.
Thanks,
Ron LaDow

madman
10-14-2005, 12:55 PM
Have a rx 7 sitting in my driveway it is my tenants in the basement of our house. It runs great and with the restriction devices removed is actually surprisingly fast tope end wise. The old rx3 with a minor change to the regulator was capable of top speeds of 135 mph i was told.

jim davies
10-18-2005, 01:04 AM
The first Wankel engined Mazda imported was the R-100. I bought one, an insurance write-off, just a few months after they were first introduced. After rebuilding it, I sold it then later got it back in deal I don't remember exactly.

Had some interesting experiences with the little gas-guzzler a few of which nearly killed me.

The reason for the lack of acceptance [and the poor gas mileage] is the surface-to-volume ratio of the combustion surfaces relative to a normal piston engine. GM dumped their licence for that reason, and Wright Aero likewise.

Felix Wankel developed other stuff, earlier. My favorite is the rotary disc-valve cylinder heads he created for a Junkers V8 torpedo engine. It ran on 100% EGR, with Oxygen and Alchohol injection. The compact cylinder heads allowed it to fit in the confines of a torpedo housing. 300HP, IIRC.

SJorgensen
10-28-2005, 08:41 PM
That is very interesting. I'd like to read more about Wankel and his inovations.

One thought I have is about oxygen injection; It seems to me that so many fuels can be used if only oxygen is available.

In an old encyclopedia I learned that liquid oxygen was used in mining. Coal dust and even ordinary sawdust was put in paper or cloth bags and soaked in liquid oxygen. These were put in holes drilled into stone and ignited. The power of the explosion was described as GREATER than gelatine explosive. I think that must have been a reference to nitroglycerine.

The advantage of this method is that the oxygen will evaporate and the explosive will become inert in a short time, if it isn't triggered when intended it will become harmless in a short time.

Oxygen is the greatest factor in how fast fuel burns, and even what fuels will burn. Oxygen can be filtered from ordinary air. Oxygen control will be the next most important engine development. With oxygen you can burn almost anything.

Imagine an engine that can burn almost any fuel.

Imagine a time machine called "Mr. Fusion"

Oh well, imagine what you will. I do.

Your Old Dog
10-28-2005, 08:49 PM
Soooo. If I want to raise some capital from investors I cough up this plan to build something that sounds outrageous but on the verge of believeablity and plop it up on a web site to give it validity. Maybe this engine exist, maybe it don't!

Theres a guy selling on eBay that looks simply huge. I drove by his place and it was a dilapidated old gas station with a small sign over the doorway! You can do magic on the web!

Arcane
10-28-2005, 09:01 PM
You can use LOX to barbeque with too... http://www.ambrosiasw.com/Ambrosia_Times/September_95/2.5HowTo.html