RXONMYMIND

Ok, alll in all I'm very pleased with the rotary engine and generally the overall performence and feeling one gets from drivng it. I'm curious to know if anyone had any idea's what it might be in the near future. Look at the piston engine 100yrs ago and compare it to taday and it's 2000% better. In contrast the rotary is only 50yrs +- and some xxxxbillions/Trillion behind in R&D. Any predictions? Me...

One day it'll surpass the piston.....and it's coming sooner than you think.

Sponge Bob Square Pants

In the near future, more comman in our cars, and also powered by Hydrogen in some applications, fairly commanly.
In the distant future, limit production due to the near elimination for the internal combustion engine in everyday passanger vehicles.

pmazda

We wont find out until we run out of oil. Our economy would collapse. Can you imagine what a for sale sign on every corner gas station would do to our real estate market?

peejay

The rotary is dead-end technology. The combustion chamber is horribly shaped and there is no way to improve it, so it is doomed because it will never be as efficient as a piston engine will be, or even as they are today.

So enjoy 'em while you can! That's my plan anyway.

domesttuner

Rotaries rule! Someone someday will figure out how to make them extremely powerful and reliable.

RXONMYMIND

Well, as strange as it might sound I don't think that the saving grace for the rotary will come from the automobile engineers. Instead, it'll have to come from the jet/turbine mfg. I suppose there are limits to THIS rotary & how it's built but not necessarily the rotary itself. As demonstrated in other applications in other industries.
I'm curious to know what the theoretical limits of this engine is. Give this engine some serious R&D $$ have Japan loosen the patent application a little to the world, I think you'd be suprised at what's already available.

domesttuner

I think you are right. It will probably develope better somewhere other than cars - so long as they still put them in 7's!

Jeff20B

iTrader: (13)

So fix the thermal prob and call it uh fixed.

Shamrock.James

hello guys:

i made that above post i think your server may be having problems....

the rotary of the futre will be PP (as it should have always been) with multiple intake points with solenoid controlled valves, the exhaust port(s) will be similar, the intermeditary housing will be removed as they will serve no purpose anymore, meaning less e-shaft flex they will have bearings around the e-shaft to give better support at higher RPM.

they will most likley be a 3/4 rotor

The planetary gears will have twice as many smaller teeth for smother opperation and will be on both sides of the rotor instead of just one.

the rotors will b 6+ piece parts with the corner triangles being the thickest part, the rotor will be bolted into place to the e-shaft, there will be 200% better oil flow bettween rotors (if the rotos arn't to have split oil sumps)
the sump will be done away with in exchnage for surge cans, allowinf even lower mounting of the engine.

Fuel will be Direct injected at the latesstage possible reducing the amount which is caught by the trailing seal, firing will be made by upto three seperate plugs with at least two next to each other.


Fuel injectors will be designed for three fuel and a custom tank will be designed allowing for the use of Hydrogen and LGP (via a high pressure tank) as well as for conventional Petrol (as a bladder surounding the high pressure tank)
meaning you will have a car that can use any fuel from any where.

the intake will just consist of a pipe to connect the snorkel to the intake port.

The engine will be assisted by means of an electrocharger, a pwerfull electric motor attached to the forward end of the e-shaft (mostlikley by some type of centrifugal clutch) , this motor will keep the engine stable at sub 500rpm idle speeds it will also be able to produce upto approx 130kw of instant torque, meaning instant go at the stab of the pedal, although this motor will not add much at high rpm, thats not it's function it is there to assist in low rpm situations.

the motor will also fucntion when the car has been shut down, by relasing the sparkplugs the electric motor can continue to spin the roros untill they have correctly cooled down at which time it would shut down, it will also be used as a stater motor, and in emergency situation where the car runs out of fuel.

finally, the e-shaft will be hollow it will hold the drive shaft for the front two wheels of the car, the clutch will be a custom designed and will be a donut in shape with no middle, it will feed into the gearbox, within the gearbox thier will a return cog, going to plate within the centre of the donut in the clutch which will feed the driveline which is inside the middle of the e-shaft (th e-shaft will need to be much bigger obviosly) this will feed to a simple differential at the fore of the car and the ussuall rear driveline would be as normal.

The engine would be mounted so far back in the car and so low that the centre of gravity would be in a place providing the best control over the veichle.

well thtas some of my ideas anyway.

oh and the engine would rev to 12,000 rpm smooth as anything.

peejay

You will never get away from the fact that the combustion space near TDC is long, wide, and thin, which is AWFUL. Ever wonder why even high-revving production engines use small bores and long strokes? Makes a nice combustion chamber shape near TDC.

Rotaries will have their place... but it will not be in cars, or any other situation where emissions and economy are a concern.

Jasil

I remember when all out race rotaries were putting out 10-20% more power than 2.0 liters, but technology has nullified the rotary advantage. Now even 2.0 liters are putting out 500rwhp on pump and 800rwhp on race gas.

Unique, black art, individualized it may be, but the rotary is dead.

rotaspec

Actually, it won't be just the rotary that will be dead in the near future. All internal combustion engines will be history in 25-50 years.
In the case of current IC engines: No fossil fuel left, increases greenhouse gases.
In the case of Hydrogen engines: Too little output for too much input. Cleaner, but still have heat output that contributes to greenhouse problems. But they could be a stopgap measure.

Unless someone invents something new and easily (read cheaply) manufactured, then the only viable alternative is electric power.
Why?: Conventional IC vehicles can be converted realitively easily. True electric designs (even now) offer a high performance (100% torque at all engine speeds) and economical running, even on conventional battery cell technology. The battery technology is where the most development needs to take place. There just won't be enough lead around to make enough batteries for all the vehicles currently on the road.

I think that this is where all vehicle manufacturers want to be in the next decade or so.

So, enjoy your noisy, smelly, fun engines while you can...

ooEfiniRx7oo

...rotary engine has longer history than 50yrs. Mazda actually bought the petent from a company in germany. Inaddition, rotary engines were/are used for aircrafts.

rotarypower101

iTrader: (1)

15B

RXONMYMIND

Well one of my idea is to split the rotary combustion chamber into two parts(imagine cupping your two hand together) and adding two spark plugs for each side of the split. This should adress the volume area of the rotary, or create a spark PLATE as opposed to a plug, thus creating a greater area of spark.

And yes the rotary has been used in aircraft engines. NOT to be confused w/a rotary piston aircraft engine which places pistons in a circle. There wasn't a viable Wankel engine before the start of WWII. Still +- a few years of the 50.

I do believe that a theoretical limit will be reached for the rotary as it has for the piston soon. Take drag car, although I'm by no means an expert, it's my underatanding that after a couple runs the engine has reached it's limits of fatigue. Running som 30+ psi will do that to an engine. Even with the aid of titanium, my point is there is a limit in terms of strength, metal fatigue ect..
The rotary with the aid of ceramic, better luburcation, lighter rotors, and better managemnt of the engine will progress. Were just scratching the surface.
For exmple how long have we stayed with the same tricodial shape of the rotor? Look at the new one. Much like the progress of propellers on a boat or the blades on a helicopter the shape og the rotor is evolving. Now the housing has to change also and not treat it as the holy grail that it isn't. If in fact the combustion area is a drawbck do to the volume area ect..change it. but that'l take time.

Should I say that perhaps a marriage of piston & rotary would be blasphme?? Take the best of both world and merge them? Hmm.....

andrew lohaus

indeed the rotary is dead, i doubt much more developement will be put into it beyond the renesis. it just isnt effeceint enough. no matter how much developement is put into it, it will never have the fuel/thermal effeciency of a piston engine. however, what could be done is a sort of heat exchanger to get the most out of that extra heat.

what could be done is to opperate tho cooling system on pure distilled water under slight vacum, or better yet develope a compound that would boil at about 180f but not freeze until -50f. this coumpound would be boiled off from the heat of the engine and the gas/steam would be used to push a small turbine that would mate to the drivetrain through some sort of hydraulic or mechanical linkage.

- with the recent advent of hybrid cars, we have gotten very good about not wasting any mechanical energy; however, even hybrid cars still waste tremendous amounts of THERMAL energy. this is a new fronteir of furthering the effeicency of cars.

even something as simple as a primitive carnot engine which creates mechaical energy out of nothing more than a temperature gradient could be employed to further the effeciency of EVERY automobile.

in that sence the rotary is dead unless is ability to create lots of heat can be put to good use.

on other fronteirs, i see an RE that uses peripherial and side ports for both exhaust and intake. think PP meets renesis. actuators would be used to switch between and combine the different tracks in order to provide an absolutely rediculous power band and rpm range.

the technology is out there, someone should have attemped this a long time ago.

Jeff20B

iTrader: (13)

15 eh?

projekt

rotary's best advantage is it's compactness. my prediction is that they'll make an extremely small one, like a 04d or whatever. it's sole purpose would be to run several alternators to keep a dc brushless motor running.

one thing i wonder though is why don't they attach rotaries to CVTs. i mean cvt's are bad with large torque and it takes a lot for a rotary to make large torque so it seems like a win win to me. get to sit in your peak power when you need it, and get a slight bump in fuel economy.

Jeff20B

iTrader: (13)

I sorta do that with the clutch pedal. I've still gotta shift though. Hmm...

tweaked

iTrader: (4)

I have pondered this myself at times.
My thoughts go something like this.
Direct injection is a must. add at least one more spark plug per rotor. make the water gap between the outside "skin" and the combustion chamber a little wider with ridges on the combustion chamber side to improve heat transfer.
Now this is where I think it gets interesting. Instead of two rotors, four, but half the width. This narrows the combustion chamber. Then you can design a better quench area for better combustion chamber trubulence and control. I feel this would also improve low end torque (assuming the same output power as the 13b).
A PP is not the way to go. it make it too easy for the spent gasses and the new ones to mix as the apex seal is passing over the port. So this means you have to have the intermediate housings, but now you need more. Now, to get closer to 100% volumetric efficiency, you only have to get half the air in each combustion chamber, but you have the same cross sectional area of the intake port to do that.
Onthe apex seals, ceramic don't seal well enough at low speads and titanium will scrape off a layer of rotor housing with every pass. I don't have an answer to this one. I think every thing needs to be thrown out and start over. some body might beable to come up with something revolutionary, but not me.
as for fuel I think ethanol should be looked into. It is made from corn it is 35% O2 and has an octane of about 115, and it's waste is CO2 and water vapor. It needs to be more wide spead before it can be considered a viable energy source to IC vehicles though. the oil companies won't let that happen. Becuase ofthe higher octane you can of course rase the copression ratio.
Then you give this motor a 9,000 RPM redline and a drive train that can accually handle it and you hvae a great car that doesn't polute.

Kenku

Actually, the shape of the combustion chamber isn't the problem. It's the fact that the trailing apex quenches a lot of the burning air/fuel.

I'm wondering what you're talking about too when you say that even high-revving production engines use small bores and long strokes. Just about every production engine I can think of that fits that description is oversquare.

peejay

Honda B18's are heavily undersquare. Some of them were pretty damn high-revving, wouldn't you say?

Sure there are lots of oversquare engines out there... but they are sacrificing combustion efficiency to get more valve area.

Engines designed for good efficiency are undersquare, or at least have small (80ish mm or smaller) bores. D-series Honda, VW watercooleds, Toyota generic motors (non high performance), Saturns... find engines that make great MPG and more often than not they're undersquare designs.

People like to say that internal combustion engines are "air pumps". Maybe in one sense, but all you have to do is look at what they're called - internal COMBUSTION engines - to see what's important - combsustion efficiency.

Kenku

Ergh, dammit. I keep forgetting the Honda things are undersquare. Funny because I have one for my daily.

However, I think I dispute your claim that engines designed for efficiency are undersquare. I'm looking at a table of engines from Toyota right now, and there's a great preponderance of undersquare engines for "normal" cars. The big standouts I see that are undersquare are the E series I4s, the M series I6s, the Prius motor, and the ZZ I4s. The V8s and V6s and all the rest of the I4s are all either oversquare or square.

Also, the B-series Hondas are gone. The K-series that replaced them are now square.

Some of the more famous engines in terms of total efficiency are also oversquare... the VQ series Nissan V6s for example. Or the Chevy LS1 or any number of others. Looking at Geo motors, yes they're undersquare, but only just; bore:stroke ratio of 0.96.

Thing is, yes, they're combustion motors. They're also a collection of parts sliding against each other; there's tradeoffs in all of this. Undersquare motors may gain you combustion efficiency, but is the penalty in increased frictional losses worth it? Longer stroke means shorter connecting rods to make everything fit, which greatly increases side load between pistons and the cylinder. Only way to get around *that* is to make the engine larger; taller deck height if you prefer that term. Longer stroke also means higher piston speeds which works against the "air pump" aspect of things.

peejay

Newer engines incorporate better combustion chamber shapes that allow the charge to be burned more quickly, so that having a larger bore isn't the handicap that it used to be. Witness how well the newer Chevy V8 engines work with their (relatively) enormous bore sizes.

Unfortunately, we can't translate that into rotary terms, since the technology rather involves getting a good amount of swirl (instead of merely high turbulence) and cramming it all up near the spark plug and the exhaust valve. (Why the exhaust valve? So the mixture nearest the exhaust valve is guaranteed to burn, so less unburned stuff is thrown away when the valve opens)

Our combustion chamber shape is pretty much fixed: roughly 6 inches long by 3 inches wide by maybe 3/4" tall in the center (where the dish and spark plugs are) and changing wildly in the poorly-accessible reaches of the chamber. As opposed to a nice decently-shaped ball of gases swirling around in short distance from the spark plug, and a maybe .060-040" squish forcing everything towards the center at TDC.

You *might* be able to redo the Wankel to be more efficient, but it would be much different geometry than the Mazda rotary. It depends on if Mazda is willing to throw away all the tooling that they've been using. The RX-8 engine still uses all of the same dimensions as the original L10A Cosmo so I don't think they will be willing anytime soon.

Longer strokes don't necessarily mean shorter rods... after all, if you're designing an engine from the ground up, you can make the R/S ratio whatever you want, within reason (piston height and hood height, mainly)

I was shocked when I learned how large the bore is on a K-series... I haven't seen any BSFC numbers of a K versus a similar output B, though. (The K's seem to own the B's as far as outright power production is concerned though!) It's definitely the way of the future.

Kenku

Well, my point about the rotaries is that the surface / volume isn't the big problme. It's *A* problem, but it's not the big one. The big one, from all the research people have done in looking at combustion chambers, is quenching the burning mixture at the trailing apex.

You're right, larger strokes don't *necessecarily* mean shorter rods but... in practical useage, they pretty much do, for the reasons you mentioned (engine height) But you know.

... and I think the discussion of bore vs stroke kind of just wandered off of any subject related to rotaries.