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Science Technology

Submersible Robot Diesel Recycles Its Exhaust 187

Posted by timothy from the looking-for-godzilla dept.
An Anonymous Coward writes: "This might be a good weekend topic to kick around. Trends in Japan has a short article on an undersea robot that uses a contained diesel. 'The engine itself is a completely closed system that needs no intake of air to run and chemically processes exhaust gas inside the robot. On-board devices reinfuse the exhaust with oxygen after removing its carbon dioxide and reuse the gas in the fuel mixture. The seawater is kept clean, as no gas is released.' Any /.'s working with this tech? Can it be applied to low emission vehicles?"
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Submersible Robot Diesel Recycles Its Exhaust More

Submersible Robot Diesel Recycles Its Exhaust

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  • Isn't this probably the exact same thing that's been done on diesel submarines for the last half a century?
    • IANANE (I am not a Naval Expert) but I'm pretty sure the exhaust in diesel subs is just being expelled into the ocean. 50 years ago when they started building them they weren't worrying about the ozone layer or the environment at all...
      • Most diesel submarines of the WWII era ran their diesel engines on the surface at night in order to charge up their batteries. Near the end of the war, the Germans invented the schnorkel which allowed them to run their engines (and expel the exhaust) while just under the surface.
        • schnorkel? Make that either Schnorchel or snorkel :-)
          • schnorkel? Make that either Schnorchel or snorkel :-)

            Nope, it's schnorkel. At least that's how it's spelled among all the history texts I've ever seen. Even the Navy spells it that way here [navy.mil].
            • All nouns in German are capitalized.
              This makes Schnorkel correct.
            • Actually, that [navy.mil] [navy.mil] you linked spells it both ways on the same page... "German Navy installed the first schnorkel snorkel)", but then futher down the page, "1,000 feet and included a schnorchel (snorkel)". A simple search on an online german dictionary however seems to favour Schnorchel [leo.org] over Schnorkel [leo.org]... because Schnorchel means snorkel [diving related] while Schnorkel is listed as something like twirl...

            • Re:Submarines? (Score:2, Informative)

              by gloth ( 180149 )
              Ok, so I'll have to throw some more authority into this... I'm German, and I tell you that there is no German word Schnorkel. There is a word Schnörkel, thich is entirely unrelated. The German work for snorkel is indeed Schnorchel.

        • Re:Submarines? (Score:2, Interesting)

          by Weh ( 219305 )
          As a side-note: the Dutch actually had invented the schnorkel I think already before the war. The Germans discovered and applied the invention later on. (I read Doenitz's memoirs so I consider it a good source)

    • Re:Submarines? (Score:4, Informative)

      by kchayer ( 161217 ) <keith@chMOSCOWayer.net minus city> on Sunday August 19, 2001 @12:07AM (#2174192)

      Isn't this probably the exact same thing that's been done on diesel submarines for the last half a century?


      No, not actually. Submarines (the non-nuclear variety) run on diesel engines while surfaced, but on battery power while submersed. Your typical garden-variety WWII sub could stay underwater for about a day before it had to surface to recharge its batteries. This made German U-boats (and other subs too, I'd imagine) quite vulderable to attack (the surfacing was to the tune of several hours) until a snorkel was developed to allow oxygen to be breathed into the motor without surfacing the whole ship.


      So no, though there is probably a small amount of reuse of some exhaust gasses, previous diesel subs still need to breath air and operate on battery power while under water.

    • No, the diesel engine was only used on the surface. Batteries powered the subs under the water. Hence the slower speed, range, etc when submerged- even though there is less resistance underwater. Nuclear solved all of that mess.
      • even though there is less resistance underwater

        Water is thiscker than air, there is more resistance.
        • Depends on the type of sub. The old WWII style with the front the same shape (okay, not exactly) like a powerboat actually run faster on the surface, not just because of diesel vs. electric power, but because it 'cut' through the water better. The new subs with the rounded conical nose run faster underwater then on the surface because of bow waves and such. Also, the rounded conical noses on subs provide a quieter profile when going through water, and most subs of the last few decades (well, at least up till the end of the Cold War) have been built to be quiet rather then fast. If the enemy can't find you, he can't stop you is the premise.

          Kierthos
  • Can it be applied to low emission vehicles

    Eventually... maybe, forseeably... no.

    This little robot cannot possibly be consuming as much fuel as your 2 ton car. Now if we can make your 2 ton car consume as much as the little robot, we're in business...
    • This little robot cannot possibly be consuming as much fuel as your 2 ton car. Now if we can make your 2 ton car consume as much as the little robot, we're in business...

      little robot? 8.2m long and 4 ton weight ain't little!

      Though I grant you it does consume less than a car. This article [u-tokyo.ac.jp] describes the power output as 5kW. This compares to 56kW on my Rover 214 (weight approx 1 tonne)

  • Hmmm. (Score:2, Informative)

    by joshyboy ( 237516 )
    Sounds great on paper, and it'll probably work quite well in smaller applications, but can this tech really be transferred to personal transportation?

    I would imagine the delicate nature of the devices would make it hard and very expensive to enlarge. Hydrogen and solar power would probably be more practical for personal transportation, but underwater (especially deep sea) you don't have much solar energy and you probably wouldn't need all the power hydrogen can shovel at you.

    • Keep in mind that the two ready sources of hydrogen are 1) electrolysis of water - no net energy gain, and 2) craking of hydrocarbons, which pollutes less than burning them, but has the same CO2 production.

      I am a big fan of solar energy, but I don't think it will be useful for vehicles for some time yet, though you could use solar power to electolyze water for H2 vehicles.

      In any case, I think solar energy is better suited to stationary or low power mobile devices, not transportation. I am a big fan of biomass energy [biomass.org] for cars. Biomass methanol has a very high net energy value, a closed carbon cycle, and is safer than compressed hydrogen.
      • In any case, I think solar energy is better suited to stationary or low power mobile devices, not transportation. I am a big fan of biomass energy [biomass.org] for cars. Biomass methanol has a very high net energy value, a closed carbon cycle, and is safer than compressed hydrogen.

        You could also produce methanol directly from air, water, and power, which might have higher efficiency (as long as you have an efficient source of energy). I'm told that the solar conversion efficiency of plants is actually rather low (your linked page didn't list figures to check this).

        Hydrogen comes by electrolysis, which is very efficient.

        CO2 comes out of air by fractional distillation or by effusion (take your pick; I'd personally go with fractional distillation). Energy cost of producing the low temperatures needed will be much less than the cost of the hydrogen electrolysis, so efficiency of this step isn't very important.

        Then you burn the CO2 incompletetly in a hydrogen atmosphere, and fractionally distill the results to get the methanol. The other products (water and some other simple compounds of carbon, hydrogen, and oxygen) can either be sold as solvents or for use in industrial processes, or burned (producing heat or power) and fed back into the system. Even the primary reaction (burning of CO2 in hydrogen) is exothermic, so you'll get some heat recovered from this stage too.

        Cleanly powering the conversion plant is left as an exercise to the reader, but either a solar heat plant or a nuclear plant should be adequate and reasonably clean (compared to fossil fuels).
    • Why should it be transferred to personal transportation? From the article it doesn't reduce the amount of pollution just where the pollution goes; it's still a diesel engine burning diesel fuel. It just closes the loop so that it can run deep underwater. The average car hopefully stays well above the water and doesn't need a closed loop. They have to provide a supply of oxygen and chemicals and filters to clean the exhaust of soot, water, CO2 and any other undesirables before reusing it. All this stuff probably gets replaced between every trip.

  • Sounds a lot like... (Score:5, Informative)

    by alien8 ( 93664 ) on Sunday August 19, 2001 @12:02AM (#2174185)
    ... the Draeger [draeger.com] closed circuit breathing apparatus I used to use when I was on a mine rescue team. The only downside to these units was the fact that after about 10 minutes of use, the air would start getting /real/ hot. The chemical reaction that took place when cleaning the CO2 out of the exhaled air made everything hot. After a half hour of use, it would start to get almost to hot to breathe, and even more so if there was strenuous work involved.
    • What all did they use to try to circumvent that problem? Couldn't you radiate the heat in some fashion without too much difficulty? (Obviously there is some problem with what I've just suggested or else it would already be done, I'm just wondering what it is)
      • Well, the old BG-174 units that I used had no sort of heat dissipation at all, unless you count the sweat dripping off your back ;-)

        The new BG-4's however, have a receptacle for a big block of ice, which does a great job of cooling the oxygen to an acceptable level.

        The only downside? For some damn reason, Draeger designed it so that as the ice block melts, it drips down your back, so you still end up getting soaked ;-)
    • at least under water, you'd have a place to dump the heat from the reaction -- a convenience that you don't have when working in a mine, huh?

      I bet you'd like to see some of those aluminum fins and fans on your Draeger like CPUs have, huh?
    • The only downside to these units was the fact that after about 10 minutes of use, the air would start getting /real/ hot.

      I suppose that's why it would work well underwater? The heat would disapate quickly with all that cold water around.
    • the Draeger [draeger.com] closed circuit breathing apparatus I used to use when I was on a mine rescue team. The only downside to these units was the fact that after about 10 minutes of use, the air would start getting /real/ hot.

      Hmmm why don't they just add an air conditioner to cool off the air you're breathing? It's not like you'd really care if the air around you gets any hotter, if you're working in a mine rescue, right?

      • Re:Sounds a lot like... (Score:2, Informative)

        by ONOIML8 ( 23262 )
        You wouldn't want to pack it around because of the weight and bulk. It's just that much more to snag on something down in the hole and if you're in rescue you're in a hurry.

        The self rescuers they gave us would actually burn your lips and do permanant damage. But, for what they are, they're really small and who the hell cares about burned lips if it's the difference between life and death.

    • You'd think that with all that water around you could dissipate some of that heat...?

  • That's pretty cool. Just try running a normal diesel in a sealed environment and watch the air pressure drop. It's not fun. Your ears will hate you for it. I still get the willies every time I play UT Pressure...
  • This article is rather dated. I wonder what kind of developments have been made on the project in the time between 1996 and now?

  • Dated!! (Score:4, Informative)

    by dragons_flight ( 515217 ) on Sunday August 19, 2001 @12:10AM (#2174204) Homepage
    One might stop to notice the date of November 22, 1996 on this article.

    Don't you love cutting edge Slashdot.

    Does sound like a somewhat useful step in submersible development, though of course it would have to surface sooner or late to refresh it's supply of fuel and vent spent fuel byproducts. Conservation of energy and all that.
    • Hey, it might not be all that cutting edge, but the technology involved may be interesting. The tech should matter more than the date imho.

      If something like this could be adapted to help clean up some of the world's auto and industrial trades, it'd be worth an extra grand or so on an auto, especially if various governments mandated it.

      Whether the mandating idea is wise or not is another topic, just my humble opinion. *grin*

    • Re:Dated!! (Score:2, Informative)

      by gilgongo ( 57446 )
      I've been noticing this ever since the rise of mass Internet use - the tendency for people to assume that what they read on the web is current, which in turn is aggrevated by the fact that so much content on the net is undated.

      I recently complained to Clay Shirky that none of his essays were dated, thereby making it very diffcult to work out whether he was talking about things in the light of certain events or not. I suppose most readers assumed he'd written them that day or something, when in fact several were over five years old.

      Ho hum. (Hows that for OT?)

    • Re:Dated!! (Score:2, Funny)

      by dostick ( 69711 )
      God damn. FIVE years ago!
      They must have been inverned something better in this time. What a waste of Slashdot.
  • Boy, this article was pretty useless. An actual explanation of how it works would have been nice.

    " Instruments aboard the robot take quick measurements of the seawater's oxygen content, salinity, temperature, and pH value at four-second intervals, or about every five meters. The robot can also be equipped with instruments to measure magnetic fields and metal concentrations in the water, and otherwise investigate the oceanic environment."

    Well ain't that nice. Is this supposed to imply that seawater is somehow used in the function of the engine, or are those sensors for other purposes?

  • My question is why not use a fuel cell, then I saw the date. That's why.

    "Mr Peabody, set the way-back machine"
    • Fuel cells have actually been around since the late 19th century, and were used successfully in NASA's Apollo program. The biggest reason that we haven't seen them in cars yet is:

      (if you listen to radical environmentalists) The Auto industry's ties to the petrol industry

      (if you listen ot the auto industry) The difficulty in coming up with a nationwide hydrogen production and distribution system

      (if you're going about it rationally) Probably a combination of the two, along with some spange.

      In any case, They certainly could have used fuel cells in the robot.

  • Not so fast. (Score:4, Insightful)

    by small_dick ( 127697 ) on Sunday August 19, 2001 @12:13AM (#2174216)
    I expect that whatever oxygenator they are using on the exhaust may be extremely expensive to implement on POVs.

    It could be a catalyst, for example, that costs big $$ to make, and could be toxic and expensive to displose of when finished.

    There's no magic here. In the past I've been a huge fan of EVs, but am disolusioned by the slow rate at which battery energy density has improved, especially considering the toxicity and expense of the new materials -- even compared to lead.

    Slowly, I'm warming up to the hybrids. Something must be done to cut down on fossil fuel usage.
    • Then diesel should be your bag, baby. Diesel cars have been getting pretty close to the mileage of hybrid powered cars for several years now. You get a good particulate trap on a diesel engine and they run just as clean as a conventional car, and that signature diesel rattle is non-existant with a good design. Put a diesel engine into the drivetrain of a hybrid vehicle would probably get incredible efficiency. As an added bonus, I've heard from several sources that diesel is very easily converted to running on pure biomass - used fry oil is the most common (and best smelling) fuel

      Diesel rocks. Only reason my car isn't diesel is because the only reasonably priced, decent built diesels are 20 year old Mercedes, and I am apprehensive about getting a car with that many years on all the systems.

      • And for all that you only have to give up power, ease of starting (especially in cold weather), and 75% of all gas stations.

        The reason nobody uses diesel anymore is because it was too underpowered and too finacky in cars. Also, all of the consumer grade diesels sounded like dump trucks and weren't particularly clean burning (especially at startup).

        I'm sure a diesel car built today would be a lot better in certain areas, but I doubt it's going to seriously beat out conventional gasoline in any way that matters to even the enviornmentally concious consumer.
    • Actually, oxygen generators are commonplace. Ever seen the oxygen masks fall from the ceiling of a commercial airliner? They are powered by small chemical oxygen generators. They are about the size of 2 cans of soup end to end, and should be relatively inexpensive. The real problem is getting one that would last for long enough and provide the correct amount.
    • In the past I've been a huge fan of EVs, but am disolusioned by the slow rate at which battery energy density has improved, especially considering the toxicity and expense of the new materials -- even compared to lead.

      Slowly, I'm warming up to the hybrids. Something must be done to cut down on fossil fuel usage.

      Fuel cells work adequately as a solution to the fossil fuel problem, if you can live with less fuel or a bigger gas tank (hydrogen is the most often proposed fuel, and can't be stored at liquid densities). Many varieties of hydrogen-based fuel cells are made from cheap materials, so cost shouldn't be a problem. This skips the carbon cycle all together (source water -> hydrogen -> water vapour -> rain -> source water).

      Another solution is to switch to burning methanol. You can either produce this by fermentation, or build it directly from air (for CO2), water (for H2), and power (solar, nuclear, or whatever). Both ways draw carbon back in from the environment, stopping the short-circuit of the carbon cycle that's causing problems with fossil fuels. Methanol can be burned (cleanly) in conventional internal combustion engines, and can also be burned in advanced fuel cells (which may be expensive; I'd just use a normal engine). It can be stored as a liquid, though you'd probably want to put it in a pressure vessel (like propane) to keep it from slowly boiling off.

      In practice, neither of these solutions will be implemented until the cost of gasoline and diesel rises to a level high enough to justify the switchover cost.
        • Many varieties of hydrogen-based fuel cells are made from cheap materials

        Really? Got references? I'd heard that they were still all mondo expensive, but that may just be Big Oil FUD.

        • Really? Got references? I'd heard that they were still all mondo expensive, but that may just be Big Oil FUD.

          One of the older types uses sintered nickel oxide powder as the catalyst. Nickel's cheap. This kind works fine for hydrogen processing; the problem is that if you use air as the oxygen source, the catalyst gets "poisoned" by the CO2 (stops working efficiently after a while).

          Another kind used aluminum oxide.

          Industry mainly uses a third type of fuel cell; I don't remember what the catalyst in it is offhand. The electrolyte is phosphoric acid.

          I did a project surveying the types of fuel cells years and years ago, but my memory of it is fading.
          • One of the older types uses sintered nickel oxide powder as the catalyst. Nickel's cheap. This kind works fine for hydrogen processing; the problem is that if you use air as the oxygen source, the catalyst gets "poisoned" by the CO2 (stops working efficiently after a while).

            Another kind used aluminum oxide.

            Industry mainly uses a third type of fuel cell; I don't remember what the catalyst in it is offhand. The electrolyte is phosphoric acid.

            Most low-temperature fuel cells utilize platinum catalysts. Platinum is expensive, but it is not the problem, since platinum content is very low (~0.2 g/cm^2).

            The most expensive parts of fuel cells are the separator plates. They are usually made of graphite or stainless steel and machining reactant channels into those materials is very expensive.

    • Re: dollars to donuts; this is what they did. (Score:4, Informative)

      by deglr6328 ( 150198 ) on Sunday August 19, 2001 @03:17AM (#2174504)
      They used a tank of O2(liquid?), a small tank of Argon or Helium for ballancing appropriate pressures/volumes when using pure O2 for smooth combustion in the diesel engine(this being the only reused gas), a tank of diesel fuel, a condensation loop to remove the H2O vapor from the combustion products (simple, since theres cold seawater surrounding the whole deal) and from the inert pressurizer and a giant canister of Lithium Hydroxide. The LiOH removes the CO2 from the combustion products via:

      2 Li(+) + 2 OH(-) + CO2 -------> Li2(CO3) + H2O.

      The only "On-board devices that reinfuse oxygen" I'm guessing are going to be O2 tanks. Maybe I'm missing something but there dosen't appear to be anything revolutionary here.
  • Man...my dog has been recycling his exhaust for years. Nothin' new to me.

  • Air-independent propulsion (Score:5, Informative)

    by Animats ( 122034 ) on Sunday August 19, 2001 @12:36AM (#2174265) Homepage
    There's a Thyssen system that uses liquid oxygen, diesel fuel, and argon [navyleague.org]. The liquid oxygen and argon are mixed to produce an "air" mixture for the engine, and then the argon is separated from the exhaust and recycled. This requires much less storage volume than carrying compressed or liquid air. Something like this is probably what's being discussed.
    • I don't remember all of the facts, and someone may have already mentioned it, but the Germans used this back in WW1 for torpedos. Very effective. Not bubble - less, though. Think about it, the combustion process generates gas. You will always have extra gas that must be expended. Additionally, the deeper you go, the higher pressure the gas must be, which really robs the efficiency of the motor. There would be an absolute limit to depth. Re-breathers really work differently - they scrub the CO2 and add O2. The CO2 doesn't need to be removed for operation with an engine. FYI, Diesel Subs only use the diesels to recharge the batteries while they are on the surface. Once under water, they run off battery. Interesting approach, but limited application. Any one heard of other modern app's?
    • Something like this is probably what's being discussed.

      But you didn't read the article so you wouldn't know for sure ? :)

      • But you didn't read the article so you wouldn't know for sure ?

        The article only says "The engine itself is a completely closed system that needs no intake of air to run and chemically processes exhaust gas inside the robot. On-board devices reinfuse the exhaust with oxygen after removing its carbon dioxide and reuse the gas in the fuel mixture." It's not clear from that what the actual combustion cycle is. But it's probably close to the Thyssen system.

        This is a special-purpose system, not a new breakthrough in engines. Only in an unusual application like this would it be worth the trouble to provide oxygen and argon supplies.

  • This could open the door for more research and explorations to be done in the deep ocean due to the lower cost of diesel engines (even this system) when compared to the expensive, heavy batteries used to power un-tethered subs. Unless fuel cell technology pan out and the development and implementation speed along faster, this could be the technology that will be adopted in the next generation of cheaper and more capable undersea exploration vessels.
    Now if they can only fit one of these systems in a hardsuit, I'd go out and buy one. (with other poeple money ofcourse)
  • The engine itself is a completely closed system

    You might want to reconsider that statement. That is unless this is a story about how there are no longer any laws of thermodynamics.

    • You're right... (Score:3, Informative)

      by 2nd Post! ( 213333 )
      It's probably not a 'closed system' in the scientific sense, but is perhaps a closed system in the 'catalyst, fuel, waste' sense.

      It must generate waste heat, for example, and I'm pretty sure that this waste heat is lost into the effectively infinite depths of the ocean, using it as a huuuge cold resevoir. On the other hand, there's no technical reason that the waste heat, in tandem with a complex metal catalyst, and a secondary cooling cycle, plus another process to trap 'waste' fuel byproducts, couldn't scrub the exhaust in such a way that it can be reused in the combustion cycle.

      More bluntly:
      water cooled air + disel => work, waste heat, emissions
      work is work
      waste heat + catalyst + emissions => hot air, hot gases, hot waste byproducts
      hot air + heatsink + ocean => water cooled air
      hot gases + hot waste byproducts + catalyst => contained wastes

      Then N months later, when the fuel is completely spent, the submersible is collected, the solid waste cartridge is cleaned, and a new supply of fuel is fed into the system.

      I'm guessing at this cycle, of course, but it's conceivable. =)
      • Please correct me if I'm wrong, but isn't complete reuse of the byproducts essentially impossible?

        Think about the energy transfer for a moment: I react fuel with O2, getting oxygenated byproducts and energy. This energy is, from the chemistry perspective, coming from the base energy levels of the oxygen atom(s). You react the components, and the internal energy of the atoms in the system decreases, releasing heat energy, radiant energy, etc [in an exothermic reaction].

        So, I then use some of this energy to make something move, and manage to reclaim 100% of the excess heat energy somehow [ignoring the fact that this is impossible]. I am still missing the energy I used to do work [moving the robot around in this case]. So I do not have the energy to unreact all the waste products for reuse. So, in order to make such a system work, you would also need a supply of another reactant to allow you to keep the net energy lower after you unreact the primary reactant.

        However, in this case you would probably have been better off just reacting with this "additional" reactant in the first place as it is a simpler system, and you can't get that 100% efficient reclaimation.

        If you still don't get it, think conservation of energy. You can't react something, use that energy to do work, not reclaim energy from the work [ok if you did, you didn't do any net work], and unreact your reactants putting everything back the way it was before. That would be a source of perpetual free energy.

        So in essence, you couldn't create a system which takes one cycle's worth of air, and reuses it entirely for each cycle. At least not if the system did any work. So you would still need a supply of oxygen [given, it may be a reduced supply if you can get a sustainable partial unreaction going to recycle part of the products back into reactants].
        • The system as described isn't impossible, I don't think. We're not talking about complete reuse of byproducts; there is waste heat and waste fuel (Nitrates and Carbon stuff), with the heat being vented into the ocean and the waste stuffs being captured for later.

          Only oxygen is recycled, or whatever combustion accelerant is used.
    • ...we obey the laws of thermodynamics!
  • about 5 years ago they could make a sub which could go under its own power for about 24 hours. 5 years later we've heard zero revolutions related to this . . . how about cars that go under their own power for 24 hours on a cupful of gasoline? And no exhaust?

    oh wait, what am i thinking, we can't have those sorts of revolutions . . . the gasoline companies would go bankrupt and our economy would fall into ruin . . .

    well, maybe if we all pretend really hard . . .
    • oh wait, what am i thinking, we can't have those sorts of revolutions . . . the gasoline companies would go bankrupt and our economy would fall into ruin . . .

      Actually, a whole lot of environmentalists would suddenly have no cause.

      See, both sides have to keep the conflict up because it's their job.

      Maybe the car makers signed a deal with with environmentalists so that they kept making cars that don't pass emissions, and people keep paying out the money for clean air, by constant car maintenance (sounds like microsoft).

      Nothing appears as things really are.
    • There is nothing really revolutionary here and sounds like somebody has hooked up a re-breather with a diesel engine. The carbon has to be extracted from the re-breather at a high energy cost to satisfy energy conservation laws. This cobustion process (if seen as a cycle) is energywise inefficient since heat is created during creation of the Calcium Carbonate (if they use lime). Strictly speaking, exhast is generated but it's delayed until the subs re-breather unit is removed and regenerated.
      /jarek

  • Why does this remind me... (Score:3, Informative)

    by Velox_SwiftFox ( 57902 ) on Sunday August 19, 2001 @01:11AM (#2174323)
    Of the Volvo (or was it a Saab)? car with such low exhaust emissions that the car would effectively clean the air on the average big-city highway? They demoed it by hooking the exhaust of a badly smoky, elderly vehicle and showed that the steadily running new car's measured emissions barely budged.

    Of course, back in the 1960's Al Capp's Lil' Abner comic introduced the concept originally.

    • Volvo advertises that, and it does it by basically making the radiator a big catalytic converter. Neat idea, albeit the metals in catalytic converters (like rhodium and platinum) are very expensive.

    • Haihai! (Score:3, Informative)

      by 2nd Post! ( 213333 )
      Volvo advertises it as the Prem-aire system, but I think they developed it in conjunction with Dow or some other chemical/manufacturing giant.

      It is a big catalytic converter+radiator, using the waste heat piped into the radiator plus some really expensive and fancy metal catalyst/complexes to break down some emission gasses, NO2, NO3, O3, whatever, into cleaner and safer compounds. It probably is similar to what the Japanese sub does too, actually, but directly on the output of it's own emissions. I would think that the sub is able to store/trap the emissions because of a second cycle that takes advantage of the ocean as a big cold resevoir, otherwise volume/pressure/gas storage becomes a big deal under the ocean =)

      The Volvo just lets the emissions free, but because they are technically cleaner and safer, it's okay, or something.
    • Actually, it wasn't Volvo like the others were saying. The system you are talking about was developed by Saab, and it is the Trionic engine management system found in every Saab 9-3 and 9-5 today. Trionic works by passing a small current through each spark plug to determine the composition of the combustion chamber and adjusts a variety of things (timing, mixture, etc.) in the engine to yield the cleanest and most efficient burn. Exactly like you said, they hooked up an old (maybe mid-60s) car's exhaust to the intake of a new Saab, and within 60 seconds, the exhaust emissions were back to normal.

  • impractical (Score:1, Interesting)

    by Anonymous Coward
    I'm sure that the substance used to scrub the CO2 back down to O2 is Lithium Hydroxide, just like in space vehicles. Lithium Hydroxide is a much more polluting substance than a little CO2. Using this idea in our atmosphere where O2 is freely available is not a viable idea.

    TAANSTFL.
  • I think an interesting point should be raised. People talk about fuel cells for power all the time, however they seem to think that Hydrogen can be gotten for free without energy expenditure. If we need to supply Hydrogen to a fuel cell, where would we get it? Electrolysis of water? That would work, but would require more energy to break the bonds than would be redeemed in the recombining generates. That's simple chemistry...no free lunch energy wise.

    • Re:Free energy? (Score:1)

      by Anonymous Coward
      they use fuel processors which take most any hydrocarbon/petroleum/etc based fuel and get the hydrogen from it by heating it and pushing it through a filter.. the waste is then burned to provide the heat... fuels for them include propane/natural gas/gasoline/diesel/kerosene/jp1/etc..

    • Re:Free energy? (Score:1)

      by Anonymous Coward
      That's true, but the advantage is that we'll have electricity for a long time to come. There's no shortage of coal in the world. (Plus I think we'll see advances in nuclear power in the next, say, 50 years.)

      Sooner or later, I think we'll see hydrogen being used on a large scale. For example, electric cars might be okay, but what's going to happen to the airlines when we run out of oil? Are we going to be back on boats? No way. Jet engines will be converted to run on hydrogen, and electricity will be used to provide the fuel.

    • The world leader in the production of liquid hydrogen is Air Products & Chemicals [airproducts.com]. Their website includes information on how they produce liquid hydrogen, and current research they are doing on powering automobiles with hydrogen.

      First, hydrogen is rarely produced by electrolysis--it's cheaper to use a reformer to extract it from waste gas at a petroleum refinery.

      Second, there are two proposed methods of powering fuel cells in cars with hydrogen. One way is to separate the hydrogen from gasoline (or propane) in the vehicle. This is less efficient, but is simpler: you don't have to replace the gas station infrastructure. The other route is to ship and store liquid hydrogen, and go through the hassle of replacing the gas station infrastructure.

      There are a lot of benefits of liquid hydrogen. There's lots of power there--but nobody should forget that liquid hydrogen is what sends the space shuttle blasting into space. While the explosion risk is real, the more likely risk is the extreme temperatures: liquid hydrogen boils at more than 400 degrees (F) below zero. If a little bit of liquid splashes on you, you can lose a limb.

  • Similar concept from SAAB (Score:5, Informative)

    by Angelwrath ( 125723 ) on Sunday August 19, 2001 @02:24AM (#2174431)
    SAAB [saab.com] had a similar concept known as the vehicle exhaust recirculation concept. It was an experiment to address the fact that the majority of pollution given off by modern automobiles occurs at startup, before the catalytic converter reaches the critical temperature needed to properly "scrub" the exhaust of its pollutants.

    SAAB's response was to develop a system that would route the exhaust of the car for the first 25 seconds into a balloon. After 25 seconds, the catalytic converter SAAB was using had heated sufficiently to properly scrub the exhaust, so the balloon's exhaust contents would then be filtered back through the intake manifold into the engine to be run through it again. The flow is regulated so as not to affect engine performance.

    The net result from this system was lower emissions than the US Ultra Low Emission Vehicle (ULEV) standard, but SAAB hasn't announced any plans to put it into commercial use.

    There is an article with more details here [findarticles.com]. Once the page loads, you can quickly get to the SAAB information by searching for "SAAB".
  • This sub is only changing the form of the exhaust. The equavilent would be to put a balloon around your tail-pipe. This sub just stores the exhaust in solid form in a filter. There is no less exhaust.

  • Don't get me wrong, this sound's pretty cool, but the article makes false claims:


    There are around 20 non-tethered undersea exploratory robots in the world, but they are of limited utility as they all run on expensive silver-zinc power cells that can be recharged no more than 50 times or so before they become useless.


    The Autonomous Benthic Explorer (ABE) [whoi.edu] built at the Deep Submergence Laboratory [whoi.edu] of the Woods Hole Oceanographic Institute [whoi.edu] originally used lead-acid batteries and now uses lithium cells.

    I worked on a building a brain upgrade for ABE. The original system runs in FORTH and C on an agglomeration of hand-coded microcontrollers and Transputers. The new system (still under development) is a PC104 stack... running Linux.

  • If you're going to have a huge oxygen tank to supply an ineffient internal combustion engine, and something to store the leftover CO2, you might as well just use fuel cells. It would be about 100 times more efficient, and give you more power per $ and kilogram
  • This is fantastic news. Hopefully this technology can be applied to cars around the world.

  • the Swedish Navy (Score:2, Insightful)

    by europrobe ( 167359 )
    We've got Air Independent Propulsion on some of our subs in the Swedish Navy... (well, as some of you would point out, it's only independent for a period of time.) The trick is to use liquid O2 and a diesel burner to drive a Stirling engine [bekkoame.ne.jp], and use enough pressure during combustion to be able to feed the exhaust out into the water. Since it's mostly CO2 it dissolves quickly. For the burner to get "air-like" oxidizer the O2 is mixed with a small back feed of reused exhaust. There is a more thorough explanation on Kockums website [kockums.se].

    This is not as clean as the drone in the original article, but OTOH, the collected exhaust in the drone has to be disposed of somewhere - it's not gonna disappear just because it's not in the atmosphere.
  • Air-Independent Propulsion (AIP) has been a hot topic in naval warfare circles for years. It's a big deal because few nations can afford to operate nuclear submarines and diesel subs are vulnerable to long-range IR detectors when they recycle the air. The solutions have been somewhat exotic- here is a good URL to check out-

    http://members.nbci.com/sabbi/pakarmy/articles/a rt _AIP.htm

    Now with diesel subs it becomes an order of magnitude cheaper to build these things as you will not require the specialized hull designs or engines. Therefore we will not be able to control the proliferation of these devil beasts.

    The world just got really dangerous again. Can you say Iraqi subs prowling the oceans looking for payback? Couple these things with cruise missiles and you don't need an ICBM or worry about missile defense.

    Darn Japanese would come up with the tool to do themselves in. Now China can come up with 300 of these infernal things to blockade Nippon.
  • Hands.

    I know any .gov in the world just about has the potential to build nuke subs. So no worry about invasion there. What about drug cartels? This is the type of low tech that they *CAN* and probably *WILL* use to smuggle contriband across borders.

    Cool, I hope gas bud goes away!

    --toq

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