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The World's Most Powerful Diesel Engine
trex279 writes "The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the world's most powerful diesel engine built to date. Each cylinder displaces a whopping 111,143 cubic inches (1,820 liters, equivalent to a cube 4 feet on a side) and produces 7,780 horsepower. The engine is about the size of a small building." The engine is intended for use in container ships.
That thing got a HEMI?
Are two stroke diesels as dirty running as two stroke gas engines?
Enjoy Every Sandwich
The engine is built by a Japanese company, but in the photographs, that's Korean on the walls.
This website has been online, unchanged, for at least two or three years. Talk about old news :-)
Nonetheless, a very impressive engine. Would it run on biodiesel?
...will the web server for this site need to be running one to survive the slashdot effect? ;-)
I wonder if it will fit in my son's Ford F-250. Let's see, with a curb weight of 6,395 and horsepower of 108,920, that would be more than 17 horsepower per pound!
The bottom of the link says:
This is a copy of the page produced by Todd Walke
Anyone have a link to the original source page?
At least read the article before posting it:
The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.
Some facts on the 14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm
I'd love to have one of those monsters. Wowza.
Classical Liberalism: All your base are belong to you.
this is pretty old and has been reposted on every automotive forum out there.
That sucker looks eerily like the M Machine near the start of Metropolis.
Life imitating art? (More likely it's just an obvious design, but still.)
just another slashdotter trying to get hits on his site. if you read the site, you see all his "articles" get 0 comments. the same thing happens to a slashdotter's livejournal/blog because they have no friends at all.
I want dis in my umveee...
Wartsila is a Finnish company. Hyundai licenses the engine technology and builds it on-site. Wartsila has also manufactures propellers in China and has recently announced a joint-venture engine factory agreemnent there.
Kinda puts a different spin on the whole thing, doesn't it?
Do NOT put petrol into the tank.
How is this news? It looks like some random quote off Wikipedia.
does it run on straight vegetable oil?
(You thought I was going to ask something else, did you?)
Please correct me if I got my facts wrong.
One of the main attractions of a two stroke gas engine is that it is simple and cheap. The reason they pollute so much is that the air-fuel mixture is pumped into the crank case along with some lubricating oil. All the engine's lubrication comes from the oil that is mixed in with the gas. That's why it belches so much smoke. The oil doesn't burn as well as the gas. (Don't flame me, I'm well aware that two strokes can get a lot more sophisticated.)
:-)
The reason for a two stroke diesel engine is efficiency. Note that the engine is supercharged. That means it doesn't need to use the crankcase as an air pump. It has valves just like a four stroke. The goal here is not simplicity or cheapness. The first thing about this engine that grabbed me is how over-square it is. Most engines have a bore approximately equal to their stroke. In the case of this engine, the stroke is about two and a half times the bore. That means the fuel has enough time to burn completely. In answer to your question, I'm guessing that this engine won't produce much soot. They are trying to burn every last atom of fuel. Of course the combustion takes place at a high temperature so there should be plenty of nitros oxide. It burns heavy oil and you need lots of temperature to make it burn. The other thing that reduces pollution is efficiency and this puppy is very efficient. They claim 50% and I believe them. It is about twice as efficient as the average car. Even a Prius is less efficient at converting fuel to horsepower.
Some time if you're curious you should google the details of the giant ships such an engine goes in. Gargantuan, one engine, one screw (propeller), zero maneuverability. You have to plan your moves twenty miles in advance. On the other hand, there aren't many crew and there's lots of room so the living conditions aren't too bad. It compares VERY favorably with a submarine for instance.
In terms of fuel consumption, and air pollution, is it better to have one huge powerful engine, or two or more less powerful engines?
If they're now making desiel engines this size for cargo, I'm curious if perhaps it's time to switch to nuclear. The waste-return equation seems out of whack for petrochemical solutions.
Why aren't there any clean-running 2-cycle gasoline engines in service, then?
Hail Eris, full of mischief...
E pluribus sanguinem
Each cylinder displaces a whopping 111,143 cubic inches (1,820 liters, equivalent to a cube 4 feet on a side) and produces 7,780 horsepower.
Of course it doesn't produce 7,780 horsepower.
Some facts on the 14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm
It seems that even the submitter doesn't RTFA.
Forget this. In memorial.
than the conventional ships used by the U.S. Navy, the LHA class of ship being the largest conventional ship (fuel oil to make steam) with the exception of the kitty hawk... the problem with conventional ships is that the boiler has to be lit off for 2 or 3 days before they are able to get underway which is an operational hazard for the navy's role in protecting the states and the rest of the world...
having the largest boilers ever produced for the navy, the LHA class ships burn approximately 1800 gallons of diesel fuel an hour, but produce around 17,000 horsepower...
i think something like this could be a viable alternative to using steam to power our fleet, only question is how much do they cost?
not that uncle sam cares
furthermore, how do you start it?
Look, I'm a nerd and would rather read/see a Warp 5 engine instead. Even a simple nuclear rocket motor would get my nipples perky!
Must be a slow news day (again).
If you like big machines, take a look at the Bagger 288. (Search for "Bagger 288" for other pictures. This one gives a good perspective on the incredible size of this thing.)
In terms of mere size, this is comparable to steam engines of 1904. The Interborough Rapid Transit Company (the "IRT" to New Yorkers) built a plant in 1904 with a total output of 132,000 horsepower. The compound steam engines had bigger cylinders than this Diesel; 42 inches and 86 inches, compared to 38 inches for the new marine Diesel.
That was the high point of piston engines. Electrical generation was already converting from pistons to turbines, and even that 1904 IRT plant had a few smaller steam turbines.
There have been much more powerful marine powerplants than this, but they're usually multi-engine turbine systems. There's an annoying tendency in commercial shipping to have only one engine on large ships, which occasionally leads to accidents.
The MAN B&W 14K98MC7 has nearly 8% more power (116,875 HP vs 108,920 HP for this Wartsila-Sulzer) http://www.manbw.com/engines/TwoStrokeLowSpeedProp Engines.asp?model=K98MC7
Great fact-checking to start 2007 with...
But you already asked it. Thanks. -1 for redundant commenting. ;->
FWIW, I'm helping to start a biodiesel co-op here in Milwaukee, Wisconsin. Get in touch if A) you see this, and B) care.
-- haaz.
The MAN 14K98MC7 is rated up to 87220 kW (vs. 80080 kW).
CC.
TaijiQuan (Huang, 5 loosenings)
Elsewhere on the site, girls being humped by dogs, and girls peeing on the groung. Engines and weird fetishes. Go slashdot
Large engines often have multiple cylinder configurations so the customer can choose how many they want based on their need, so it's often better to list the power per cylinder than for the entire engine.
boldly going forward, 'cause we can't find reverse
The company that designed this engine has some history. They were Rudolph Diesel's employer in the late 1800s.
http://en.wikipedia.org/wiki/Sulzer_Brothers_Ltd.
--Pat
The product page has a couple of PDFs with actual technical data and some nice photos. Oh, and in terms of real units, the power output is up to 80 MW for the largest model.
Does it run Linux?
printf($randomline(sigs.txt) \n "-- "$randomline(authors.txt));
-- myself
... would one go about starting that thing? and I wonder how long that operation would actually take....
Conversion of heat into any other type of energy achieves it's maximum at 33% (the other 66% heats up the environment, according to the Laws of Thermodynamics).
No, the maximum efficiency for a heat engine is given by 1-T(low)/T(high) (absolute temperatures), which can be higher than 33%. If you can make T(high) high enough, and T(low) low enough, you can get 99% efficiency, or 99.9% efficiency, or whatever you like.
Arguably, these laws have not been proven, and they can't ever be proven. But they have been unchanged for quite some time now.
No, actually they have been proved, mathematically, within their realm of applicability, and to within the level of statistical certainty that's inherent in them (which is not an issue for a macroscopic device).
A breakthrough like this would not go unnoticed and thanks to my thermodynamics professor I would be the first one to hear about it (he's a nut about engines). So I think that part of the article is something someone tried to spike in to give the engine more of a wow-factor
No, the problem is just that you don't understand thermodynamics.
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> Conversion of heat into any other type of energy achieves it's maximum at 33%
;-)
d PropMEEngines.asp?model=K108ME-C6
This is probably only true for american internal combustion engines
For engines built in other regions efficiency goes by the Carnot Rule:
http://de.wikipedia.org/wiki/Carnot_wirkungsgrad
On the other hand the sulzer engine is rather small you can have
at least another 30.000 HP from MAN ( or better 168g/kWh(Sulzer) efficiency):
http://www.manbw.com/web/engines/TwoStrokeLowSpee
look for 14K108ME-C6
97.000 kW @ 171g/kWh
or same power at better efficiency:
77.000 kW @ 161g/kWh
wish to be the first to welcome our new, giant diesel engine overlords...
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You're wrong. Go read up on heat engines and the various thermodynamic cycles you can use. There are power plants in operation that achieve 59% thermal efficiency.
Suffice it to say, it is a very well established science, and all quite provable both theoretically and in practice.
Alcohol, Tobacco and Firearms should be the name of a store, not a government agency.
Hnm...the article is a little disreputable. As far as I can tell, here's what happened. Some guy named Todd Walke scraped photos and diagrams out of the pdfs on this Wartsila web page. He made his own web page, which, AFAICT from Google, no longer exists, possibly because he got a take-down notice from Warsila. Meanwhile, a bunch of other people have mirrored the page. So in other words, the Slashdot story linked to somebody's copyright-violating copy of a copyright-violating copy of some of Wartsila's pics. As other people have pointed out, it's actually not the world's most powerful diesel engine, either. Oh well, the pics are cool!
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The original question asked whether the marine engine would pollute the same as small two stroke gas engines found on some old cars, motorcycles and chainsaws, etc. What you may be used to in the diesel world isn't the same as cheap two cycle gas engines.
Check the wiki article on two stroke engines. http://en.wikipedia.org/wiki/Two-stroke_cycle It has a good animation. Note that the crank case is very definitely used for pumping air. Also note the absence of valves.
BTW. I used to race motorcycles. I have built/repaired/tuned many engines including two strokes.
If the engine is as big as a house, how big is the gas tank?
Not the diesel you buy at the pump anyway. It runs on heavy fuel oil, which is ... almost a different thing altogether. As for starting it, If I remember correctly, they use some kind of compressed air starter. ... grain of salt usage might be prudent.)
(I am not an marine diesel engineer, but, I remember talking to a friend who is. My memory is not what it used to be, so
"Consistency is contrary to nature, contrary to life. The only completely consistent people are the dead." A. Huxley
Will it do the quarter mile at 325mph, in four seconds? Top fuel engines produce that much power now, with only a tiny fraction (about 1/20) of the number of cubic inches. Sure, top fuel engines have a fairly high failure rate and need to survive under load for only 5 seconds at the very most, but there is a lot to be said for a compact power plant.
It's interesting that these big engines are directly connected
to the propeller. To stop, you turn the engine off. To reverse,
you turn off the engine and restart it in the other direction.
Bigger engines will only encourage bad ship design. One engine, one screw, one rudder. It's cheap to build and run, but a failure of any component leaves the boat adrift. Crude oil carriers especially are a problem, because running aground is so gucky. Why doesn't the world insist on two engines, screws, and rudders for tankers?
Well, I thought it would go into the next generation Viper :))))
I am putting myself to the fullest possible use, which is all I can think that any conscious entity can ever hope to do.
I read a couple articles in TNY a few years back about the massive engines used by coal-carrying trains here in the USA. The author stated that hybrid engines, basically diesels generating the electric power for the electric motors (one per wheel) were the only type that could provide enough power to pull the 2-3 mile long trains in use. So: is it really a power-to-wieght (or size) problem? Otherwise I would have to wonder why the locomotives are hybrid but this here monster is pure diesel.
https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
Now look at Diesels. The smallest working Diesels are the little glow plug engines that are used to power model aircraft - actually semi-Diesels whose spiritual big daddy is the classical single cylinder 9 litre like the Bolinder. The biggest are these marine monsters with their two-metre throws. But they all are constrained by a few parameters that are broadly the same - the MEP and the mean piston speed.
At the normal running speed of about 100rpm the engine in the article is doing about 6-7 metres per second. At its normal cruising rpm of about 2000, my car engine is doing 33 revs per second * 2 * 90mm stroke - or 6 metres/sec. I haven't checked, but I fully expect that the working MEPs are within the same ballpark. It's nice to see that engines ranging from grammes to kilotonnes are constrained by a simple law based in metallurgy and tribology.
The other nice thing is, that with the exception of the tiny toy engines, all Diesels work more or less the same way, and the direction of change is by downwards replacement - technologies developed for large marine engines find their way ultimately into small engines. Modern auto engines with their electronic solenoid operated injection systems are basically a shrink of the marine technology of the 80s and 90s. Turbochargers also undergo shrinkage as their technology moves from marine to auto use, so we get the variable vane turbocharger turning up on entry level cars.
It would be wrong to force too many analogies, but there are resemblances between Diesel systems development and computer development that are perhaps more than skin deep.
Pining for the fjords
This truck runs on Diesel with three engines that deliver 36000 horses together, so much more than this engine...
http://auto.howstuffworks.com/question647.htm
--- Hindsight is 20/20, but walking backwards is not the answer.
Is there a whopping starter motor? :)
Can you push start it?
In fact the most efficient rpm range of the base level Volkswagen 1.9L engine - a very high volume unit - is around 1900-2400 rpm, and that is a small engine.
Furthermore, the torque required to turn a prop depends on a lot of factors - even for a small boat, prop matching to engine is a pain. For the size of boat I run, props range from about 12/10 (12 inch diameter, 10 inch pitch) to maybe 24/18. The 12/10 would be used with a small high revving Japanese engine like an Isuzu, while the 24/18 would be used with a direct drive heavy engine from the 50s or 60s. Note that, to a crude first spproximation, the volume of water shifted by one revolution of the prop is proportional to diameter squared * pitch, therefore the 24/18 is nearly 8 times bigger than a 12/10. Big slow props can be more efficient at shifting water, and direct drive avoids the power loss in gears, but also big props allow you to do clever things with surface finish to minimise noise and vibration. That, metallurgy and Reynolds numbers will ensure that container ships continue to use big engines and big props for the foreseeable future, but powerboats can continue to be pushed along by silly little props and high revving low torque gasoline engines until the fuel runs out.
Pining for the fjords
http://www.mes.co.jp/english/business/energy/energ y_01.html
The k98mc has 7780 hp PER CYLYNDER, up to 93360 hp (at the crank)
People who think they know everything really piss off those of us that actually do.
Do you just make things up for fun and post them on slashdot?
In fact, just FYI, there are several engines available now that convert heat energy into velocity at more than 90% efficiency - high expansion hydrogen based rocket engines! Really amazing devices, really.
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Imagine a Beowulf Cluster of these Engines. I wonder if they Run Linux?
Seems to have gone down in flames. Too bad.
---- Booth was a patriot ----
Interesting example! I can easily imagine how that would be consistent with the laws of thermodynamics, since T(high) would be the extremely high temperature of the burning fuel mixture, and T(low) could potentially be a lot lower. Do you have any data you can point us to on real rocket engines?
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Would it be feasible to design a reactor that wasn't a security risk? Maybe that pebble bed reactor concept?
Absofuckinglutly! You may have to upgrade the fuel line.
Why was this parent modded 'Funny'?
Could you brew up enough biodiesel in algae tanks on a supertanker that the ship would be essentially self sufficient? I doubt there would be much room for a lot else, but when you're talking about supertankers, "not much room" is a relative term.
What he can't kill, he has sex on. Trent.
Hey pal, if you had read the story you linked to, you would have known that the engines in this truck are JET engines, with diesel injected at the exhaust outlet to generate flames and smoke for visual effect.
It's interesting that these big engines are directly connected to the propeller. To stop, you turn the engine off. To reverse, you turn off the engine and restart it in the other direction.
I used to work for a marine electronics company, which frequently had me on board ships of all sorts. I've stood inside the crankcase of a running marine diesel (idling at 7RPM), swapping out an oil pressure sensor for the engine management computer. The access to the oil pressure sensor had me working less than two feet from where the crank throw passed every nine seconds or so - just keep your body clear of it!
I don't think I've ever seen a direct-coupled engine (there's almost always at least very rudimentary gearing), but it certainly wouldn't be impossible - all you'd need would be a variable pitch propeller, which is commonplace anyway.
Fire and Meat. Yummy.
In fact gasoline engines tend to be thermally limited - just look at the peak power rating compared to the SAE continuous rating for most small automotive engines. Your two stroke would probably need to be just as heavy as the four stroke to achieve the same continuous power rating, given the life expectancy of automotive engines. So what is the point?
Pining for the fjords
So it's a small ship engine eh?
..just imagine the huge torque wrench they need for the cylinder head nuts. It has to be airlifted in from Sears.
Microsoft OLE DB Provider for ODBC Drivers error '80004005'
/engines/header.inc, line 91
[Microsoft][ODBC SQL Server Driver][SQL Server]Cannot open database requested in login 'motorprogram_temp'. Login fails.
"Everything is adjustable, provided you have the right tools"
"Hey pal, if you had read the story you linked to, you would have known that the engines in this truck are JET engines, with diesel injected at the exhaust outlet to generate flames and smoke for visual effect."
Right 'pal', it has jet engines all right, but contrary to what you think they run completely on Diesel. I think that's pretty cool, it beats elevator sized cylinders if you ask me. The added Diesel for the flames is just to improve the mile-gaseage...
http://www.shockwavejets.com/shockwave.cfm
I'll grant it to the first replier that says the engine in the article is 7780 horses per cylinder times 14 cylinders, but who's to say you can't mount 10 of these jets onto a frame and call it even bigger? Judging by the pictures the Jet engine is more compact per horsepower than the elevator box.
--- Hindsight is 20/20, but walking backwards is not the answer.
Rocket engines are far under 90% efficient because a large chunk of the energy goes into the kinetic energy of the stream of hot water vapor (in an H2 + O2 rocket) flowing out the bottom.
I find this kind of thing hard to wrap my mind around, because of the way kinetic energy transforms between frames of reference. For instance, suppose your rocket has now reached 4000 m/s with respect to the ground, and its exhaust velocity also happens to be 4000 m/s. That means that your exhaust is at rest relative to the ground. That particular exhaust is now right back at the same (zero) KE it had when it was fuel in the tanks on the launchpad, so exactly zero of the chemical energy is being wasted as KE of the exhaust --- in that frame of reference. On the other hand, you could consider the frame momentarily moving along with the rocket. In that frame, P=d(1/2mv2)/dt=mva=0, so the efficiency of that same rocket, at that same instant in time, is exactly zero. For the same reason, the efficiency is horrible, in the ground's frame of reference, during the time shortly after launch.
One thing that I would expect to work against a rocket engine, as opposed to some other kind of internal combustion engine, is that it has to carry its oxidant along with it in a tank, and accelerate that oxidant. A car engine doesn't need to do that. OTOH, friction is zero once it's above the atmosphere, whereas for a car cruising down the freeway, the efficiency is exactly zero due to friction. I guess for a rocket the thermodynamic limit on the efficiency could be very favorable if the combustion temperature is very high (which it is), and the effective exhaust temperature is much lower (which I'm not so sure about -- would depend on the details of how it's expelled, I guess).
It's also not clear to me that thermodynamic efficiency is even the right quantity to worry about. For instance, solar-powered ion drives probably have very low efficiencies, due to the high kinetic energy of the exhaust, but that doesn't matter because the energy is coming from solar panels. Even for a chemical rocket, designers seem most interested in getting a high exhaust velocity, because the mass of the whole rocket on the launchpad depends exponentially on that. A high exhaust velocity is good, even though it may actually result in lower efficiency (at least at some stages of the launch).
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Hate to be standing next to that sucka when it throws a rod.
Um... all a rocket engine does is accelerate a high temperature gas - so the energy of the steam leaving the nozzle is not loss, it is the whole point of the engine.
Now, using that to accelarate am object may have useful or non-useful metrics. But it is hard to call that efficiency, though. (For example, accelarating a stationary object using a rocket engine takes more energy than picking the object up and throwing it. But we still don't try to throw the space shuttle into orbit for some reason...)
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What makes this work is that the chamber temperature is way higher than can be contained by any materials that we can make - so they cool the chamber walls (which would be an efficiency loss) but they cool them with propellants (so that the energy lost is put back into the system). So the engine itself has virtually no losses - and if you put a large enough nozzle on it, you can take it to just above the boiling point of water. So the engine can go from 3300 C (the SSME combustion temperature) to about 50 C (nozzle exit is way below atmospheric pressure, so the boiling point of water is lower). Efficiency = 1 - 350/3600, >90%. Several engines like this were designed, but since it would only make sense on a very long term deep space mission, I don't think anything this efficient was ever really built.
As a more concrete example, the Space Shuttle Main Engines (SSME) have a combustion efficiency of 99%. So the only thing that makes the total efficiency less than 99% is that the engines must operate in the atmosphere - so the nozzles cannot be too large (the exit pressure needs to be close to one atmosphere). The overall system efficiency of the SSME is 76%. More efficient engines have been made (look at the J-2 or any upper stage hydrogen engine), but this one everyone is familiar with.
Note that an inefficient rocket engine is a really bad idea - the SSME are 6.4 GW reactors, and are only a few meters long. Think about it - any losses in the engine (wasted heat) would need to be radiated away. What temperature would it have to be to radiate away 5% of 6.4 GW?!?
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I hate to get all Sherlock Holmes on you folks but the article is slightly inaccurate. FTFA... "The Aioi Works of Japan's Diesel United, Ltd built the first engines and is where some of these pictures were taken." This is untrue because if this were actually in Japan then why would there be Korean (Hangul) writing all over the bloody poster boards. In fact this the Doosan Engine factory in Changwon, South Korea and I know that because I was just about hit by a gigantic forklift while is was driving through that very factory this morning. Believe me those engines are big. Though IMHO Hyundai Heavy is much cooler.
But why are 2-strokes particularly desirable?
As somebody else pointed out, a two stroke has approximately twice the power for the displacement, which means that you could more than halve the weight of the engine for similar performance in a car. After all, once you've eliminated several hundred pounds of engine and associated materials, you need less power for a given amount of performance. Two strokes also don't need quite as many parts as a four stroke, and have some advantages elsewhere.
Now, I remember seeing an ad on television a couple years ago where a group had apparently developed a clean, computer controlled two-stroke marine engine. The EPA apparently includes Direct Fuel Injection 2-Stroke Marine Engines as 'low pollution' for marine use.
Europe and Japan have a very large market for small city cars where the buyers aren't so concerned about power and really don't give a fig about engine size as long as it works well enough on a test drive.
I wish US car makers would stop trumpeting engine size and horsepower quite so much. Believe me, it's a somewhat neglected market because the profit margins aren't out there, but there's quite a segment in the USA that's the same way.
As somebody else said - It'd be a risky development process and there are technological and cost hurdles to meet.
I don't read AC A human right
Yes, but such systems add cost and reduce efficiency, and how much electric power do you need for a cargo ship? Slapping a generator onto part of the system shouldn't be difficult. Better yet, use a seperate generator so you keep electricity with the big engine off.
I don't read AC A human right
You're comparing a show truck to a production engine intended for serious commercial use. Fuel efficiency is of great concern.
Even if somebody did tie ten of those jet engines together, the engine would still be biggest in it's class (until somebody builds an even bigger one).
I don't read AC A human right
The reason we don't throw the space shuttle into orbit is because the sudden acceleration will easily kill the astronauts, and then you've got to worry about how the payload on the shuttle will fare. The Shuttle uses rocket engines to give a relatively slow acceleration through the flight over a longer time to minimise g-forces and floating space graveyards.
Hopefully we'll get something faster than the officially fastest diesel trains in the world... We're far too behind to worry about things like electrifying our lines after all... Sigh
Now there's one hoopy frood who really knows where his towel is!
So the engine can go from 3300 C (the SSME combustion temperature) to about 50 C (nozzle exit is way below atmospheric pressure, so the boiling point of water is lower). Efficiency = 1 - 350/3600, >90%.
No, this is just the limit on the efficiency from the laws of thermodynamics. The actual efficiency is certainly much, much lower. Also, there's no way that the exhaust is at 50 C at the point when it loses contact with the nozzle, so the real thermodynamic limit is going to be way less than 90%.
As a more concrete example, the Space Shuttle Main Engines (SSME) have a combustion efficiency of 99%.
No, this is definitely not the thermodynamic efficiency of the engines, considered as heat engines, because even according to your earlier (incorrect) calculation, the maximum possible efficiency based on the laws of thermodynamics is lower than 99%. This figure probably represents the fraction of the fuel that undergoes combustion.
Note that an inefficient rocket engine is a really bad idea - the SSME are 6.4 GW reactors, and are only a few meters long. Think about it - any losses in the engine (wasted heat) would need to be radiated away. What temperature would it have to be to radiate away 5% of 6.4 GW?!?
No, obviously the wasted energy isn't going away by radiation, which is a very slow process. The wasted energy is going into KE of the exhaust, heat of the exhaust, frictional heating of the atmosphere, and KE of the early stages of the rocket.
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I didn't see any mention of the turbo in the referenced article (or a casual chase of Google links). If the main crank is turning at a relatively sedate 102 RPM, how fast is the turbo running?
The Russians have won. They have made the world a cesspool of distrust, greed, fear and hate.
"You're comparing a show truck to a production engine intended for serious commercial use. Fuel efficiency is of great concern."
I think the show truck is a serioudl commercial use truck too: I don't think the people running it do it for charity and they must take running it very serious because it can be very dangerous to drive on the ground at such high speeds...
I guess they say the diesel engine with cylinders is the most efficient way to burn fuel (which I doubt because it can't be ideal because it loses energy through heat), but that doesn't count the weight into the equation. If a cylinder block always beats a jet engine in fuel efficiency, those 'jet' airliners would have a different name.
--- Hindsight is 20/20, but walking backwards is not the answer.
This is *very* old news. So old that some of the facts are severely outdated (as some remarked).
And this news is also so old that spreading PR-material for free was a *good thing to do* at that time.
Not copyright violation as many writers seem to think.
I think the show truck is a serioudl commercial use truck too: I don't think the people running it do it for charity and they must take running it very serious because it can be very dangerous to drive on the ground at such high speeds...
I didn't mean that the truck isn't commercial, it obviously is. But you're comparing a $500k truck, that's standard run is only a few miles and lasts under a minute with an engine meant to power a multi-million dollar ship and move billions of dollars of merchandise for months on end. Basically, how many $500k trucks could you build and still make money off from them, and how many of engines in this class are moving ships carrying goods right now?
I guess they say the diesel engine with cylinders is the most efficient way to burn fuel (which I doubt because it can't be ideal because it loses energy through heat), but that doesn't count the weight into the equation.
Most efficient way to burn [i]cheap[/i] fuel. From what I've read, these things burn stuff ranging from 'filtered crude' to 'stuff barely liquid after refining'. It's nasty stuff, but also half the cost of even cheap 'diesel' fuel like what they feed semis.
If a cylinder block always beats a jet engine in fuel efficiency, those 'jet' airliners would have a different name.
Then why isn't everybody running around with a jet engine? Why do we move cargo in huge sea transports and railroad rather than flying the cargo everywhere in these highly efficient planes? Why is about the only production land vehicle with a turbine the Abrams tank? Why are they powering huge cargo vessels with huge diesel engines instead of turbines if they're so great?
Fuel efficiency is secondary for jet airplanes, the primary concern is the ability to travel at over 600mph. Propellor(Turboprop) planes are still more fuel efficient than jets, but they aren't as fast, and the market has spoken. We'd rather pay some extra money to get to our destination an hour or six faster.
Another factor would be reliability. Given the workload that these diesel engines undergo they'd be having to rebuild the engines monthly and replace them every two years. Not economical.
I don't read AC A human right
And with small modifications to the injectors and fuel pump (if needed) it might run fine on most vegetable oils, rapeseed, sunflower, peanut ,palm....
Save the World now not later!
First calculate how many horsepower you get per cubic inch. An auto engine does about 1/2 HP per cubic inch. A good old radial airplane engine, say the R4360, gives about 3/4 HP per cubic inch. Now do the math for this diesel-- about 1/14th of a HP per cubic inch. That's very low volumetric efficiency.
That's mor ethan a theoretical issue-- each cubic inch of displacement has to be surrounded by a corresponding cubic inch of iron. Iron is heavy. calculate the horsepower per pound-- for a car engine it's about three pounds per horsepoer. For the R4360 it's down to about ONE horsepower per pound. For this diesel, it's a whopping FOURTY SIX POUNDS PER HORSEPOWER. This diesel is over FORTY times heavier per pound than a good aircraft engine.
Engines do not scale up well-- even at this really low volumetric and weight efficiency, the engine needs sophisticated piston and head cooling systems just to keep it from melting down.
I wasn't able to spot anywhere in the pictures the giant elastic band used to start this sucker. Exactly how does that work? Or does all fourteen crew assemble along the top and give a giant heave to fourteen lawn-mower pull cords in perfect unison?
+ million+times+hours%2Fyear
For all those people worried about the fuel consumption level, a Wikipedia page states that a container ship can carry as much as $300 million in cargo. In our highly disposable society, you'd need to depreciate that figure by $100 million in the first year post-production.
http://www.google.ca/search?hl=en&q=three+hundred
Loaded to capacity, the goods conveyed could be depreciating on the open market by as much as $34,000 per hour in transit. $34,000/hour buys a lot of giddy-up.
Well, the aviation diesel engine seems to have come a long way since I went to school. Thanx for the info.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
..in terms of specific fuel consumption - the amount of fuel needed to produce a given amount of power and consequently drive the ship a given distance. This is much more important that the power-to-weight ratio of the engine in the intended market; the weight of the engine pales in comparison to the weight of the fuel and every last bit of "fuel efficency" is key. Gas engine, regardless of design, run at around 0.3kg/Kw-h (takes 0.3kg of gas to produce 1 Kw for 1 hour)...the RTA96 runs at 0.163kg/Kw-h. Put another way, an auto engine runs at ~25% thermal efficency versus ~52% for the diesel.
Ganging together 109,000 hp of auto-design gasoline engines would require _doubling_ the fuel capacity (and consequently the exhaust emissions) for the same range...efficency comes in many forms.
Facts do not cease to exist because they are ignored. - Aldous Huxley
Well, no.
Truck: 12,000 HP per engine times 3 = 36,000 HP.
Wartsila engine: 7780 HP per cylinder times 14 (for the largest) = 108,920 HP.
Why do you think that your truck even comes close to the output of this monster?
Virg
> If a cylinder block always beats a jet engine in fuel efficiency, those 'jet' airliners would have a different name.
The other response addressed a lot of this, but I'll toss in that there are two things that change considerations for jet engines versus Diesels, and both point toward jet engines for aircraft. Firstly, planes don't need torque, they only need thrust. Jet engines are great for generating thrust, not so good at torque. Second (which derives from the first) planes need speed, not really power. Both is handy, but if it was economical to build rail guns to get planes off the ground they'd do it. Speed is king, since it's the forward motion (and only the forward motion) that keeps it aloft.
Both of these benefits are lost on a huge oceangoing vessel. These vessels need a huge amount of torque to drive the screws, and speed is irrelevant after a certain (low) amount. Therefore, jet engines would be very inefficient for these applications.
Virg
As promised
7 426264)
"I'll grant it to the first replier that says the engine in the article is 7780 horses per cylinder times 14 cylinders," (http://slashdot.org/comments.pl?sid=214476&cid=1
You Are Absolutely Right.
--- Hindsight is 20/20, but walking backwards is not the answer.
There is a little more to it than that - a key point being that it is impossible to "throw" something to orbit - you can give it altitude and velocity, but not in the right direction. (Essentially, either you throw it too hard and put it in escape or the orbit you threw it to intersects the Earth again). By "throwing" you can greatly decrease the strain/requirements put on your rocket engine, but you still will need a rocket engine.
The other thing I will say is that for reasonable structures, you need to fly through the lower atmosphere at mach 25. Ouch.
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No, this is just the limit on the efficiency from the laws of thermodynamics.
No, I could have calculated the theoretical limit at 90.3%. The described rocket engine will get very close to that - rockets are by far the most efficient machines ever made by man. Look up losses for standard nozzle flows sometime - they are tiny! That said, this engine was never built, so who knows.
there's no way that the exhaust is at 50 C at the point when it loses contact with the nozzle
Um, so what is it going to do? I'm talking about a vacuum engine, obviously - so what is the exhaust going to do, just decide to ignore physics? The exhaust expands to fill the nozzle no matter how big the exit is - you just have to make it really long so that you do not get shock losses.
this is definitely not the thermodynamic efficiency of the engines
If you read carefully, I did not claim it was the thermodynamic efficiency of the engines. In fact, later in that same paragraph I gave the thermodynamic efficiency of the engines at 76% - and gave you a reference. So you will have to come back with a little more than "you're wrong", more like "I know the secret that makes you, NASA, and all of physics wrong!" The 99% is one measure of how close they come to ideal thermodynamic efficiency. The only other factors in this type of engine is friction losses in the nozzle (tiny for large engines - surface vs area effect) and imperfect flows (which is also very small for real engines).
The wasted energy is going into KE of the exhaust
To show why this is a dumb measure: The energy of the exhaust exactly equals the energy coming in with the propellants. The outside of the engine never sees any of the energy inside it, since the heat "leaking" from the chamber is put into the propellant and thrown back into the engine. So if you count KE of the exhaust as "waste", then all a rocket does is waste. (And of course, in a vacuum there is no heating of the atmosphere)
I believe what you are trying to get at is that the way to move something using the least amount of energy is to push off of the most massive thing available. So trains that use the Earth as their reaction mass are "more efficient" than aircraft which uses the atmosphere which are more efficient than spacecraft that have to push off of their own fuel. That is true, but is not "thermodynamic efficiency".
To prove it to you in a mind game, pretend that you could get some "unobtainium", which is as strong as you would like it to be and yet weighs very little. Build an engine, where you have a huge rocket nozzle attached to an arm that turns a generator. Once you turn on the engine, let it get up to about 4.5 km/s (that's why it is made from unobtainium), and then connect the generator.
The exhaust from the rocket nozzle is at rest in the frame of reference of the generator, and is 350 K. That is the exhaust temperature. The chamber temperature of the rocket engine, 3600 K, is the inlet temperature. So you now have a generator that is 90% efficient. If you want to calculate the power supplied, it is the thrust of the rocket times the velocity (in this case 4.5 km/s).
You can use the engine in many ways, so it is best to clarify what you mean by "efficiency". "Thermodynamic efficiency" is a very precise term, and a useful measure for engineering.
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How about a rail gun placed on the side of a tall mountain? Not only do you get a ten mile (16 km) or more track to accelerate on, but you also cut through the thickest part of the atmosphere too.
The rail gun's acceleration (somewhere around 200 g's or 2 km/s^2) and the passage through the atmosphere might be too much for delicate loads (such as humans and entire spacecraft), but it should be fine for sending bulk materials (such as a 10 ton hunk of iron or a heavy-duty steel container filled with water) into solar orbit (or high earth orbit if a receiver is there to catch it). After all, similar sized iron and rock meteors make it through the atmosphere to hit the ground, even if they do lose a good chunk of their mass.
On a different note, could the Earth's magnetic field be used to accelerate a suborbital mass to reach orbital speed and direction within a few minutes, thus reducing the speed needed to be attained by rockets or mass drivers substantially? It should be relatively easy to lob a projectile a few hundred miles up with no horizontal velocity, perhaps with conventional explosives.
How about a rail gun placed on the side of a tall mountain?
;-}. It could probably be made to work, but you would still need a rocket engine to make your orbit not intersect Earth. (Think about it this way, your final orbit always has to include the point where accelaration stopped). I don't think you could use Earth's magnetic field to change much - though that would be interesting to study, at least. You might be able to use it to make your orbit not hit Earth, which would be a big win.
That is the clasic almost-reasonable suggestion. You are still going mach 25 in the atmosphere, which I still say ouch to
The real problem with such ideas is that you are competing against a rocket engine. At the current market levels, a rocket engine is pretty hard to beat - if you only fly a few times a year, your construction costs per flight are about 10% of the total project cost divided by the flight rate. For example, if you could build it for $10B, you need to generate $1B per year to cover construction costs. If you fly 10 times a year (which would be really hard to convince people of at this point), you would have to allocate $100M per launch for the construction costs. And then add to that whatever a launch costs incremently.
First, we have to prove the market exists. Then we can build "really big toys!"
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If I'm not mistaken, the highest overall efficiency would be achieved if you could scale the exhaust speed to the speed of the rocket (which cannot be taken to its extreme since the launch mass would then be infinite, even if the energy needed would be quite finite). In other words, when the rocket has done a cumulative delta-V of 2 km/s, it should be exhausting gas at 2 km/s. I'm basing my little theory on the conservation of energy and that if all your exhaust has zero kinetic energy with respect to your reference frame of interest (generally the planet's center), then all of the kinetic energy must have gone into the rocket.
This strategy economizes on energy early in the launch, when the penalty for lugging mass to that velocity is small, and economizes the mass that must be lugged far into the launch by economizing mass later in the launch.
This is somewhat done in practice by burning heavy fuels such as kerosene in the lower stage and hydrogen in the upper stage.
"Why are they powering huge cargo vessels with huge diesel engines instead of turbines if they're so great?"
Because for pushing large ships through the ocean big cylinders are more efficient... The fact that jet turbines aren't up to that task doesn't make them not useful, they're just not useful for that particular task. Why is it that 'diesel people' think that there is nothing in this world except applications that need torque without caring about the weight of the engine.
Sure, in a ship the diesel cylinder block seems unbeatable, and it's pretty neat in vehicles, but for speeds over about 200MPH or if it needs to be lifted into the air, it's not so holy anymore.
There is actually an underwater jet turbine design (the pursuit marine drive) that claims to be very efficient for propulsion of boats, but its just a research thing and hasn't scaled much yet (the company that designed it sell much smaller versions for other applications) (http://www.newscientist.com/article.ns?id=dn3321 and http://www.pursuitdynamics.co.uk/)
"Fuel efficiency is secondary for jet airplanes,the primary concern is the ability to travel at over 600mph."
Tell that to boeing and each airliner, who make/choose airplane and engine designs where fuel efficiency is the most important factor. The 500-600Mph cruising speed is a minimum requirement, but given that requirement the jet engine is the most efficient engine (so far).
"Propellor(Turboprop) planes are still more fuel efficient than jets, "
The turboprop is more like the jet engine than the cylinder block: A turboprop engine is not a pistoon and cylinder block, it is actually a turbine engine too just like the jet engine, but then with the propellor connected to the turbine.
http://en.wikipedia.org/wiki/Turboprop
I seems there is some kind of religion for which the diesel cylinder block is holy and anything else is blasphemy and/or inferior, even if it is an engine that runs on diesel, and suggesting that it's better than the cylinder block in any way is blasphemy because there is nothing that a diesel cylinder block can't do best.
Oh well, there are also people who claim that a Harley is the most reliable motorcycle you can buy...
--- Hindsight is 20/20, but walking backwards is not the answer.
Power is the measure of work per second and work is the measure of force over displacement. Torque is a measure of work, thrust is a measure of force. Both can be used to calculate the power of an engine and because the thrust of a jet engine is combined with a high velocity, that results in a lot of work per second, hence a lot of power.
That paragraph above seems lost on most diesel cylinder block fans. no torque does not mean no power, it's just silly to think that it does.
"Firstly, planes don't need torque, they only need thrust. Jet engines are great for generating thrust, not so good at torque."
Agreed except that jet turbines don't have an propulsion axle to measure torque on, so torque is not a measurable factor for jet turbines. Torque is not measurable for the propulsion strength of jet turbines (see http://en.wikipedia.org/wiki/Torque).
How now having a torque measure makes the jet engine any less useful is a mystery. Some applications need torque, others thrust.
"Second (which derives from the first) planes need speed, not really power. "
Sorry, but planes need a lot of power: for speed you need power. Power is not the same thing as torque. Jet turbines have a thrust measure but also power measure (the 12k horsepowers for the ones in the truck).
--- Hindsight is 20/20, but walking backwards is not the answer.
I think the key point here is that it's impossible to throw the Shuttle into orbit for one clear and obvious reason. Superman is still missing.
> How now having a torque measure makes the jet engine any less useful is a mystery. Some applications need torque, others thrust.
This goes to the heart of it, so I need only address this. Ships propel themselves by twisting a screw in the water. Jet engines are badly suited to this task compared to Diesel engines, and moving a ship by pushing it above water is very inefficient compared to twisting a screw. Since we're discussing applications involving moving a container ship on the ocean, the argument stands. Sure, there are many applications where a jet engine would be better, but they would be offtopic, since we're discussing an engine specifically designed to move a ship.
> Sorry, but planes need a lot of power: for speed you need power.
My second point does derive from the first, remember. While saying that planes need only speed is a semantic point (you're right that power is necessary to move a plane forward) I will say in my weak defense that a plane doesn't necessarily need to be moving forward to fly. Having watched a Piper two-seater "flying" like a kite in a gale force wind at an airport near my house, I can say that it's so. With tongue in cheek.
Virg