Slashdot Mirror
Australian Team Working On Engines Without Piston Rings
JabrTheHut writes "An Australian team is seeking funding for bringing an interesting idea to market: cylinder engines without piston rings. The idea is to use small grooves that create a pressure wave that acts as a seal for the piston, eliminating the piston ring and the associated friction. Engines would then run cooler, could be more energy efficient, and might even burn fuel more efficiently, at least according to the article. Mind you, they haven't even built a working prototype yet. If it works I'd love to fit this into an older car."
Trust me, I have a PhD in engineering.
Put ALL effort into engines that don't use fossil fuel at all. Thanks.
This is 2014, where's my flying car?
Oh wait, I can't afford it.
Please give me grooves for an extra 2 miles a gallon in a way that the local shop can fix (looking at you, battery/hybrid-CVT/regen-braking monster).
Extra fuel efficiency would be nice, but I am most excited about the prospect of the engine itself lasting longer. Less friction = less heat, less wear & tear, etc. A cool, frictionless engine could potentially last for half-million miles before needing replacement. At my paltry 10-20k miles per year, I could potentially never have to buy another car again.
So, the idea is that the grooves in the piston will create little eddies of air that separate the combustion chamber from the oil galley, right?
Here's the problem - the air that forms said eddies has to come from somewhere, and there's only two options: the combustion chamber, or the oil galley.
Still, to a gear head such as myself, it's still a pretty cool idea.
An enigma, wrapped in a riddle, shrouded in bacon and cheese
But we already have an engine that doesn't use piston rings. And it's not like this idea hasn't been tried before either on reciprocating piston engines, usually with a whole series of problems. Mostly compression issues.
Om, nomnomnom...
Only works in theory? Don't tell me, rubber pistons?
Table-ized A.I.
If they haven't even built a working prototype then how can they be seeking funding to bring it to market? surely they are just seeking funding to prototype to see if it is even viable to bring to market?
Is the no ring design coupled with a spherical rotary head. What ever happened to Coates International?
They are re-inventing labyrinth seals. They come in a variety of shapes and sizes. They've been used for decades in jet engines and other applications where the pressure drop across the seal in not large. They have not proven practical in applications with higher pressure drops across the seal because they don't seal completely. There is always some leakage.
They shouldn't test in Australia. Down there, piston engines convert smog into petroleum.
Table-ized A.I.
From TFA:
A 'virtual model' equates to 'proof-of-concept'? Since when?
I thought this was about this article which uses a pistonless pressure wave and makes all the same promises.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
My reading comprehension may be failing me here. Does the article say Benz and BMW are already using this technology?
"It’s the ideal set-up to make the most of each spark, already used in advanced engines by the likes of Benz and BMW for the win-win it produces in boosting performance while cutting consumption and emissions."
But no prototype. I am not a physicist, but I ran it through a little thought experiement. If it is some sort of standing pressure wave, it would have to move with the piston, that may be possible, but difficult. The problem I see is that any type of wave would hbe dependent on the frequency/speed of the piston in the cylinder. Therefore, it would have to be there across the entire operating range of the engine, not just it's peak power band. That is a large range. If it falls off anywhere along this range then you get oil control issues, compression issues, or both just as if you had bad rings. Oil control leads to plug/combustion chamber issues and expensive oil replacement. Compression issues lead to huge ineffeciencies, that would offset some or all of the gains from reducing friction. In addition, while the friction may be less, this pressure wave would by its nature have to exert some pressure on the piston and cylinder walls to seal. It may be less friction and less metal to metal contact, but not zero friction. In short a laudable goal, but seems more like a funding grab than a workable idea.
Silence is a state of mime.
Seems like a lot of extra work. Why not just mod an existing design with their piston?
Never let a lack of data get in the way of a good rant.
Put ALL effort into engines that don't use fossil fuel at all. Thanks.
Gasoline, diesel, etc don't have to be Fossil Fuels. We can make them with a biological process for example. These processes are basically carbon neutral since the carbon emitted during internal combustion recently came out of the atmosphere.
That makes this Slashdot-worthy.
A boxster engine.... are they looking to fix the Subaru STi ringland problem ? Some stock and modified Subaru STi haves piston rings failures from cylinder 2 and 4.
I wouldn't dismiss this right away.
If the physical features on the piston provide resistance to gas flow along the piston/cylinder annulus similar to that provided by piston rings, they wouldn't need a close-fitting piston - therefore no expansion coefficient headaches. It may also be that the hydrodynamics tend to center the piston in the cylinder, which would reduce contact events and scuffing wear.
You could probably get a feasibility go/no check with a few weeks' worth of modeling. The resonance interactions in the piston grooves when the combustion pressure front reaches them would be very interesting to see.
Gasoline's energy density is nothing special, the advantage it has is in procurement, having resulted from millions of years of energy collection which means the effort of getting to it is trivial. And compared to the alternatives, it's a messy bit of junk.
You are confusing storage not collection. The energy was collected over the very short time span of a plant in a swamp. The millions of years that turns this into crude oil is just chemical transformation and storage.
Gasoline is a simple molecule that can be created in a variety of ways. One way is the distilling of crude oil. Another is biological production via engineered photosynthetic organisms. Same energy source of the fossil fuels, the sun, however carbon is coming from the current atmosphere not carbon sequestered millions of years ago. Its a much greener process.
What about when the piston is motionless or slow?
You'd have to keep the CR low enough to not overcome the pressure wave of the ringless design. That means you'd lose efficiency in the engine. Reducing friction is a great concept but I'd still like to see the math involved as to how they'd get the efficiency out of the engine vs. a traditional design and how they'd keep the crankcase temps down and the oil clean. Most of that black/brown gunk in your oil at an oil change is blow-by, products of the combustion process. Even with piston rings you get a certain percentage of this and it raises the temps of the engine not just with friction but with hot gasses escaping into the crankcase. Don't get me wrong, I'd love to see internal combustion go beyond what we have today but it seems that there are already advances in direct injection and forced induction that are making smaller more efficient designs more powerful. If you want an internal combustion engine without rings (or wipers in a Wankel) then why not a turbine engine? It was tried before but I guess people were worried about melting the asphalt with the exhaust gas temps.
Harrison's Postulate - "For every action there is an equal and opposite criticism"
The biggest barrier to the adoption of ringless pistons is pre-existing technology
which is mature ( and works as needed ) and which has already paid for its development costs.
Billions of dollars and millions of man-hours have been consumed
in the development of Otto Cycle engines. Existing engines do not fail
because the piston rings are worn. They most often fail due to poor maintenance
practices, negligence, or abuse, which would kill an engine using ringless pistons just as quickly.
Additionally, whether this ringless technology is adopted hinges on
whether money is made available to develop it to the point where it
can be used in mass-produced vehicles. When a manufacturer can
meet its goals using an engine which has piston rings and spend less
money , or spend significantly more money using ringless pistons
which give marginal improvements at best, it is extremely unlikely that
a manufacturer will choose the ringless technology which involves more
risk for a reward which is not proportional to the risk.
There is an old patent on such ringless tech. There really are
very few new ideas in internal combustion engine tech.
http://www.google.nl/patents/US3745890
Much larger gains in power and efficiency are available by using electrical
or pneumatic devices instead of camshafts to control the movement
of valves in an engine. If I had to bet on what would be the most likely
tech to actually be used in production engines this is where I'd put my
money. Such tech IS used in engines of both Formula 1 cars and MotoGP
racing motorcycles. But all those engines ( on which hundreds of millions of
development dollars / Euros / yen have been spent ) still use piston rings.
That ought to tell you something. Of course it is possible that the engineers
at Ferrari and Honda and Renault and BMW are not as sharp as the folks in
Australia with their ringless pistons, but smart money would not bet on that
being the case.
Finally, if you REALLY want your engine to last, use the best synthetic oil available
and perform all other maintenance as indicated by the manufacturer, and you will
probably get bored with the vehicle long before it wears out.
=
Turbulent obturation rings of this kind (well, technically I guess these are obturation cannelures) have been used in a lot of applications because they have some interesting properties. For instance they are used in mortar shells. When you drop the shell down the mortar barrel, you essentially want it to fall without retardation so the primer gets a good hard strike and the propellant ignites 100% of the time. However you want as much as possible of the propellant gas to do the job of propelling the projectile, without blowing past it in the barrel. You ALSO want it to be as consistent as possible so the CEP of where the projectile lands relative to the target is as small as possible. So this isn't impossible, but it's not easy either.
From the TFA:
"... that an absolute seal isnâ(TM)t that important, and eliminating the friction generated by the rings on the cylinder wall can have far-reaching effects on engine design on the whole "
" ... that the whole thing is blowing a bunch of hot air?"
If they _ CAN _ use that bunch of hot air to form a seal, and achieve a drastic reduce of friction in between the piston ring and the bore itself, I feel that it's time for the return of the ceramic engine.
The chief reason why ceramic engine doesn't make it into the mainstream despite having had under research since the 1970's is that the friction in between the piston ring and the wall of the bore itself result in the wearoff of the ceramic material in the form of a pile up of fine ceramic dust inside the chamber.
If what the vendor said is proven to be true, then we should bring the ceramic engine back to the fore-front.
Muchas Gracias, Señor Edward Snowden !
Why not eliminate the engine completely? Just aim in the direction of the destination, detonate, and surf the pressure wave.
With the engine-less car you can't take it with you, but if you don't make it on the first shot you won't be around to care.
2010 Corolla - it'll last forever, which is long after you'll fall asleep at the wheel from boredom...
I seem to remember running those well beyond the typical life of a current car engine. In fact, I remember my roommate pulling his squareback into a VW small local shop: 15 minute swap, a week to rebuild, another 15 minute swap - and good for another 100K...
I thought they were shutting down thte Australian car plants (by 2017)
There are no economically feasible systems like you say in use any place on Earth, so you are incorrect, you should have prefaced your flippant comment with, "Theoretically".
How do I know, because I'm part of a working group to do just that, we're in contact with scientists and companies world wide and nobody can make it happen on a large scale at cost, let alone at a profit, which is the only way that technology will become available.
Looking for funding without a physical proof of concept?
How much would it cost to create a prototype? Get a used lawnmower engine, find a piston from a slightly larger used lawnmower engine (up to here you spent about $50), then turn some grooves in there and see how it purrs.
What are we talking about? a couple hundred bucks?
It would cost way less to try this in real life than all the computer simulations. Something smells fishy.
The important part, anyways. The Valvular Conduit - patent # US 1329559 A
http://www.google.com/patents/US1329559
Without rings, there would be no seal, so you either machine the gap to within a single atom, or you lose the pressure/increase friction.
I can see them collecting a lot of money to fund such a device, but it won't work how they're saying they will do it.
I'm thinking if you had a micrometer sized spiral grove going up the cylinder wall the oil would stay in the grove to act as a fluid bearing and seal. I think part of the problem is that pistons and cylinder walls expand and contract with temperature.
BMW tried this on their cars and they leaked a lot of oil. Toyota removed the rings on the Tacoma and after 120,000km the engine was really loud with valve noise.
It is a good idea to reduce the friction in the engine but you will have some nasty results if things go wrong.
Well, technically, pistons without rings. The piston and cylinder are machined precisely enough that they don't need rings. But here's the catch to what the Aussies are talking about as well as lots of other exotic engine designs. If it can't be made for the same or less money than present engine designs, it'll never get off the ground. And if it can't be maintained for the same cost, it'll eventually fade away. Popular Science and Popular mechanics are littered with unusual game-changing engine designs e.g. the 6-stroke engine that has a steam cycle to make use of the wasted heat energy or the Wankel.
A whole team is working. Yet no prototype has been produced. What's their main activity then? Pushing pencils? Having meetings to organise funding? It all sounds a bit strange.
I hadn't the slightest objection to his spending his time planning massacres for the bourgeoisie... (P.G. Wodehouse)
Carbon build-up.
Eventually, all engines suffer some form of carbon build-up that effects both engine compression and the internal exhaust pathways. For example; the exhaust valve pathways and EGR. Even with modern engines, proper fuel metering, and modern additives (polyetheramine), crap and crud still builds up over time.
Life is not for the lazy.
We already have engines that work based on air holes.
http://gamehacking.org/vb/threads/12747-nensondubois-codes http://twitter.com/nensondubois_
http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
When running an engine with cracked piston rings, lube oil will start to enter the combustion. This will produce toxic black and foul smelling exhaust and the engine "will be burning oil".
You mention an engine where a specific feature, specifically the piston rings, has failed, so it's no surprise that it's operation would be undesirable. I will counter with 2 stroke and wankel/rotary engines, which burn oil by design. Burning oil isn't as much of a problem if you design for it.
The Australians are working on a design where the piston rings won't be necessary. It could end up that they need a new lube system for the piston rod/crankshaft, or it could end up being an insurmountable problem(for now). I like that they're looking into it though. It reminds me about how HD platter arms are suspended by air flow from the rotating platters. High enough pressures might cause the air to act more like a liquid.
I don't read AC A human right
how do keep the piston cool? seems like spraying oil would get into the grooves and stop the air waves from being formed.
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Also will meet a grim fate in stop-and-go driving if fielded when they carbon up.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
Dynex has brought the technology to the proof-of-concept phase, in which virtual modelling of the âoeair-sealingâ principle looks promising enough to get to work on the real thing.
So, they haven't gone beyond a computer simulation of this? Yet,...
Weâ(TM)ve reached the point where we need to secure corporate backing to push the project through the development stage towards international commercialisation,
They think that a computer model is good enough to get this thing into mass production? Without even building a single prototype engine? What the hell, am I missing something here?
Nearly all small model aircraft engines run air cooled with pistons without rings. I built control-line aircraft models in the early 70s that used .049 cc and .20 cc and .35 cc displacement engines that had no rings. These engines were mass produced by Cox, Enya, SuperTigre. So what is the big deal here?
A horse.
Give it another hundred or so years... We might find that horses end up more popular than gasoline filled vehicles again. Not saying that horses will regain their former dominance though.
I don't read AC A human right
Interesting to see how the pistons will last under the heat of combustion without no active cooling via rings to cylinder wall.
Trust me, I have a PhD in engineering.
Model aircraft engines have been using grooved pistons since the 60s, and it worked fine. I have seen it on bigger engines too - but usually backed by at least one conventional piston ring.
There is nothing new in using grooves instead of rings - it is simply a case of optimising the groove design to make it work better for larger pistons.
(And contrary to what another poster has said, cooling is not an issue either - it is easy to oil cool pistons, if required.)
Model airplane engines don't have piston rings because those would be cost prohibitive, not because it's better technology. Model airplane engines wear extremely fast, have a low efficiency when you compare the burn energy to the output of motion and are extremely polluting.
I was promised a flying car. Where is my flying car?
To add on to what user Firethorn has said, try imagine an engine that needs no cooling.
The very reason we need to COOL our engine because the metal that we use in our engine can withstand heat up to a certain limit, and beyond that, the engine starts to melt.
Ceramics don't have that problem. Some ceramic compounds can withstand thousands of degrees of heat (and for that they have been used as shields for the Space Shuttles) and they are excellent insulators !
Serious research has been carried out on ceramic engines since before 1970's, by almost all the developed countries (America, Europe, Japan) and prototype engines had been developed.
The main problem so far is that, unlike metal, ceramics are not as durable against friction. Very fine ceramic dusts will fall out as a result of the friction, and combined with the fuel, it become "sludge"-like, jamming up the chamber.
There are a lot of places inside an engine where there are frictions, but the MAIN place which friction takes place is in between the piston ring and the bore wall.
If what the TFA says is true - that they can manipulate the air to become a "force" and takes the place of the piston ring, which means, the friction in between the piston ring and the wall of the bore is gone, then, the number one problem facing the ceramic engine is solved !
Muchas Gracias, Señor Edward Snowden !
That applies now.
The only reason it is not economically feasible is because it is so cheap to dig fossil fuels out of the ground.
Allegedly, we are now past peak oil, and the price of fossil fuels should start going up. Eventually it will be economical to produce synthetic hydrocarbon fuels using solar/nuclear/other power and either biomass or CO2 and water - either because the technology has improved, or the products have risen in value, or more likely, both.
I'm guessing that wasn't on their radar screen...
Now , dont be too hasty in condemning this as fruitless.
The Aussies were merely formulating a way to slowly burn off that nasty engine oil. Why, they would only end up changing it and winding up with a bucket of old dirty motor oil. This way it is vaporized along with gasoline and any remnants of it are spread invisibly through the atmosphere. Theyve eliminated a very messy product to deal with.
Imagine how tough they will look with their vehicles blowing a manly stream of black smoke in their wake.
All perspective.
*Repent!Quit Your Job!Slack Off!The World Ends Tomorrow and You May Die!
Why isn't there a car refurbishment industry, or at least a cottage industry?
There are always those models of cars which through design refinement seem to reach a "bullet-proof" stage where the major mechanicals are extremely durable and are produced in massive scale, like the Camry.
Assuming they don't rust out (which seems to be less a function of corrosion than mistreatment and unrepaired body damage), you would think that someone would be in the business of refurbishing them to a near-new kind of state.
There's a ton of third-party new parts and the cars were produced in such numbers that there's a lot of spare parts from other vehicles, too. Seats could be rebuilt and reupholstered. About the hardest part to "fix" would be dashes and interior door panels, but these could come from spares.
US labor is probably too expensive, but it's not hard to see the rebuilding of components (engines, transmissions, seats) happening overseas and assembly happening here, or just do it all overseas and ship them back by the shipload.
For the clearances to be right at operating temperature, they have to be far greater when cold. On cold starts, the blow-by will probably pretty bad - enough to fail US federal emissions limits; doubly so for California's.
Wikipedia covers it pretty well but it's an average of RON and MON.
http://en.wikipedia.org/wiki/Octane_rating
I've never had an engine fail due to piston ring wear.
Most haven't but that doesn't mean something potentially better than piston rings isn't worth trying. Piston rings work pretty well but their very design is sort of a workaround solution. In theory they shouldn't be necessary at all. A design that could eliminate them altogether could in theory be a very big improvement in engine efficiency and reliability.
Oh and I have had a piston ring fail. Even if they don't fail they will cause wear which results in reduced efficiency over time.
Seems to me this may be an idea looking for a problem.
Only if you don't understand the engineering tradeoffs being made. Piston rings generate friction, they require complicated lubrication systems, they can and do fail sometimes, they are expensive to replace, they complicate engine assembly and design which adds cost, etc.
Bring back the rotary, without ANY APEX or side seals.....
I am the unwilling control for my Origin.
and the idea that we can - in a perfect world - eliminate the need for work allowing people to concentrate on the betterment of themselves and their fellow man.
Has it occurred to you that in many cases work IS a way for people to concentrate on the betterment of themselves? Work is not some horrible thing to be eliminated or feared.
Gasoline, diesel, etc don't have to be Fossil Fuels. We can make them with a biological process for example.
All so-called fossil fuels come from biological processes. The only real difference the ones we make and the ones we dig up is when they were made. The ones we dig up were biological processes that took place a long time ago. This means it requires comparatively little energy to get them because we just dig them up. If you want to make them the energy required for processing becomes a MUCH bigger piece of the economic and chemical equation.
These processes are basically carbon neutral since the carbon emitted during internal combustion recently came out of the atmosphere.
No they will not be carbon neutral because the conversion process will not be 100% efficient. The processing of the fuel will require energy which baring some unexpected breakthrough in energy technology will result in net carbon being emitted.
When I think of knock, I think of bad bearings, main or rod. Pre-ignition I call pinging.
Knock and pinging are synonyms per standard usage. Pre-ignition is technically a separate phenomenon. Knocking is when fuel/air explodes outside the normal envelope of the combustion front. Pre-ignition is when the fuel/air explodes prior to the spark plug firing. It's common for people to confuse the two and to use the terms interchangeably but among us engineers this is technically not correct.
Makes me think it's junk that will never work right.
Not if you use water injection!
You would steam clean that baby!
I currently use it on my turbo 2.3 with great success.
You can't take the sky from me
Carbon build-up.
Perhaps a ceramic engine could run hot enough, that carbon at critical places will burn. Perhaps ceramics can be made with surface which resists carbon-build up. Perhaps ceramic material can be made so that it catalyzes burning of carbon. Perhaps some space can be reserved and gas flow around the piston can be designed so that carbon build-up happens at places where it does not matter. Perhaps increasing efficiency enabled by higher temps will simply allow so clean burning, that amount of unburnt carbon is reduced to the tenth of current minimum and it will not become a problem until it's necessary to overhaul the engine anyway.
To summarize, I'd wager carbon build-up is just an engineering challenge.
Had me thinking though.. and ones that could create a pressure wave might not work at high RPMs , due to the time required to build up the air cushion. Since they haven't built a working model, never mind prototype, I guess they haven't cracked that egg yet.
Why not revisit rotary if they're going to waste all their time on the ICE? OTOH, I'm a garage junkie from the 60s and I love the smell of gasoline, and the best days of my life were spent doing things like helping to install a chromed GMC 6/71 blower on a hemi in a loud hot garage.
Yet ... Even *I've* gone electric. Mind you, I've disconnected the governor and installed plus size Tesla batteries on a wee li'l scooter ;-)
Eventually, all Internal Combustion engines suffer some form of carbon build-up
compressed air and steam engines just to name a couple don't suffer from carbon build-up in the cylinders
gosgog:
Interesting thought but wait 'till they build & put at least 100,000 miles on it. Speaking of U.S. Built cars (late 60's) , Mustang, & Cougar were great but then went to Toyota sold it because of planned on a job move to Vancouver, they wanted to tax all my stuff so didn't go.
I bought a used 66 Cadillac 4 door, with about 35,000 miles. Moved from Portland, Ore, to Houston Texas to live (great city). I finally got rid of it after elec windows & some other minor stuff, final mileage close to 400,000 miles! A few years later with my own business based in Houston I leased a used Lincoln town car...finally close to three hundred thousand miles. Sold it 'cause I needed money to buy an airplane for my business, and bought an old pickup to get back & forth to my local airport. Today (retired) I live in Asia, & currently drive a used Nissan sedan.