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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."
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).
I'm sorry but the energy density of hopes and dreams is nowhere close to that of gasoline.
fnord.
But hopes and dreams are of endless supply. Gasoline not so much.
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.
Trust me, I have a PhD in engineering.
Would you care to expand upon that? Or is this the scenario we are looking at below?
If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong. -- Arthur C. Clarke
Or perhaps we simply have a loose troll?
much of left-wing thought is a kind of playing with fire by people who don't even know that fire is hot - George Orwell
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...
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?
Trust me, I have a PhD in engineering.
Heh heh. Posting anonymously when resting your authority on the strength of your name rather than the validity of your argument. Have to feed the troll on this one.
Science advances one funeral at a time- Max Planck
Forget hopes and dreams, power it on a person's sense of self-satisfaction. Although low yield, it's in vast abundance.
Science advances one funeral at a time- Max Planck
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.
So... in other words, you're saying that the whole thing is blowing a bunch of hot air?
Science advances one funeral at a time- Max Planck
You sound like the people in my grandmother's village in 1905 when the first car drove in - "It won't last - you can't feed it like you can a horse".
This also removes the piston-to-liner pathway as a way of cooling the piston head - the hardest part of an internal combustion engine to keep cool.
How the ringless piston works:
In place of the rings, each piston has numerous small, angled grooves, semi-circular at their apex. With the small clearances between them, the movement of the piston creates high-speed eddies -- air pressure working like metal rings to cut leakage and loss during the compression and combustion strokes.
“That means there’s no metal-to metal contact between the pistons or rotors and their mating cylinders or housings. Virtually no friction means the mechanism needs no lubrication and there’s no wear and tear on major components,” said Trigg.
There’s an important by-product here, too. Putting an “air cushion” around the periphery of the combustion chamber creates a stratified air-fuel charge – an injection profile that enriches the mixture in the centre of the chamber and leans it up towards the periphery.
It's not a typo if you understood the meaning!
Trust me, I have a PhD in engineering.
Would you care to expand upon that? Or is this the scenario we are looking at below?
I'm an engineer too, but without PhD. I don't know what he was thinking of (or even if he is an engineer at all), but I can say one major flaw that I noticed. The piston rings serves two functions and they only consider one.
The article deals with combustion, which is on top of the piston. It never mentions what is below, which is the piston rod and the crankshaft. The connection between those two needs to be well lubed, but the construction makes it really tricky to lube a "run away" bearing. The solution is to make an "oil fog", which sticks to everything, including the cylinder below the piston. When the piston moves downwards, the piston rings scrape off the oil from the cylinder and provides a clean surface for the combustion.
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". Even worse the oil burns badly and leaves behind soot, which will damage/block the valves. Some of it will stick to the cylinder wall and not be removed by the piston rings, which mean it ends up in the lube oil. The higher the amount of soot in the oil, the worse lubing ability it has. Eventually you have an engine with enough oil, but no lubing.
In short: no piston rings will destroy every valve and bearing in the entire engine and replacing it could be cheaper than repairing it.
I consider this to be a far more serious problem than anything the article mentions and I find it rather shady that they completely avoid this rather serious issue. It isn't like it is an unknown problem. If you run big engines like trains or ships, then you will periodically test the oil for soot (and other stuff related to other defects) to detect faulty piston rings before the engine is wrecked. Anybody working in the engine industry should know this.
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.
That has been solved for a while. Oil jet to to bottom of the piston. They have been doing that for a long time in racing and motorcycle engines.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
So will this mean that sleeve valves will be practical.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
That's how the Prius works. It's partly powered by smug.
That I'm right, and you don't like it, doesn't mean I'm a troll.
Eyeroll. "In the long term we are all dead". For the lifespan of everyone who is alive to read this today (discounting a war that destroys industrial civilization), the internal combustion engine will be the dominant powerplant for transportation. Deal with it.
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 !
It is nothing special from a volumetric energy density (MJ/L) point of view. It's in the same general range as all primarily petroleum based fuels which are liquid at room temperature and atmospheric pressure; more toward the lower end of the range. It is substantially more than liquefied gases and solids such as coal and wood.
Petrodiesel 37.3 MJ/L
Crude Oil 37.0
Gasoline 34.2
Gasohol E10 33.2
Jet A 33.0
Biodiesel 33.0 for comparison
Diesel is both cheaper (in normal countries, not the ridiculous US pricing structure) and higher energy density.
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.
'Knock' is detonation. The words you are looking for are 'piston slap'.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
One of the reasons for going from 2-stroke to 4-stroke was heat. So the "fix" to your problem is to go to 6-stroke engines, with extra strokes for cooling. Also, water injection was used to fix that issue in other engines as well. There are lots of ways to fix that. No oil in the chamber doesn't mean you can't spray the back of the piston with a cooling agent (oil in today's cars). I can fix that problem easily in any of a hundred ways (finding the most efficient would be the trick), and you've proposed no other solution to the problem fixed by the air seal.
Learn to love Alaska
Probably harder to hide the smoke and mirrors in an existing engine.
If you are not allowed to question your government then the government has answered your question.
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.
I'm not switching from gasoline until someone makes an engine that will run on distilled suffering of hippies.
Violence is like duct tape. If it doesn't solve the problem, you didn't use enough.
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
'Knock' is detonation. The words you are looking for are 'piston slap'.
No, 'piston slap' is something different. It's what we do to people who quibble about terminology. ;)
I don't care if it's 90,000 hectares. That lake was not my doing.
Fuel injected cars are quickly learn a new fuel map when the fuel changes.
Even 10+ year old cars do that to an extent. My turbo charged engine has two maps. There is the basic programmed map and a learnt one based on readings from the knock sensor, so it can handle fuel of varying octane ratings.
When I think of knock, I think of bad bearings, main or rod. Pre-ignition I call pinging. Different people have different terminologies, possible due to culture.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
What the heck are you talking about? Piston rings are there to save money by not requiring precision honing of the bore and piston. If you select the materials correctly you have never needed piston rings.
Just about every model airplane engine now uses a piston with no rings, and it scales perfectly well. It's just a matter of how much it costs, and the cost has been prohibitive.
And yes, you do need to match the coefficients of expansion in some combinations of materials, and also taper the bore so that it doesn't "bell-mouth" from expanding more that the top, where it's hot, than the bottom. Either that, or allow it to be mismatched, put in even more taper, and allow heat and expansion to create the proper fit. In either case, chrome the bore, or put on a hard anodized surface to keep it from wearing out prematurely.
People knew this all 50-60 years ago, and used it in some cases. It's not cost-effective, but it's certainly feasible.
Brett
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...
I'm not switching from gasoline until someone makes an engine that will run on distilled suffering of hippies.
Not all 'hippies' are created equal. I tend to consider myself as somewhat hippy-ish. I believe in peace, love, understanding, environmentalism, nuclear power, GMO foods, high-technology, 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.
Note that the vast majority of 'hippies' disagree with me vehemently on nuclear power and GMO foods (and some disagree on the high-tech). From my point of view as a scientifically minded person though, I see these as being the sensible environmental low-impact choices of the present day.
As for your gas-guzzler (and mine) - I look forward to the day they no longer exist.
My book about LSD and Self-Discovery
Also on facebook as: DroppingAcidDaleBewan
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.