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Lasers To Replace Sparkplugs In Engines? 351

Posted by samzenpus
from the lift-the-hood-and-avert-your-eyes dept.
An anonymous reader writes "For more than 150 years, spark plugs have powered internal combustion engines. Automakers are now getting close to being able to replace this long-standing technology with laser igniters, which should enable cleaner, more efficient, and more economical vehicles. Price and size have been issues holding up such an advance, but a Japanese team is set to announce they've overcome those hurdles."
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Lasers To Replace Sparkplugs In Engines?

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  • by plover (150551) * on Wednesday April 20, 2011 @06:09PM (#35886218) Homepage Journal

    Seriously, just think of the potential hacking uses of a pencil sized high powered laser! Cutting and drilling through hardened steel. Remote ignition of fires or detonation of explosives. Actual blinding weapons in a flashlight case.

    I'm afraid they'll be too cool to be let out in public.

    • by dlingman (1757250) on Wednesday April 20, 2011 @06:16PM (#35886266)
      I just realized that we're planning on arming our self parking, navigation aware vehicles with burning lasers. I thought Skynet day was yesterday...
    • Re: (Score:3, Informative)

      by Anonymous Coward

      Remote ignition of fires or detonation of explosives.

      Your comment was duly noted and a shiny black DHS van was dispatched to your location.

    • by causality (777677) on Wednesday April 20, 2011 @07:17PM (#35886802)

      Seriously, just think of the potential hacking uses of a pencil sized high powered laser! Cutting and drilling through hardened steel. Remote ignition of fires or detonation of explosives. Actual blinding weapons in a flashlight case.

      I'm afraid they'll be too cool to be let out in public.

      All you'd have to do is find a way to carry around an engine, a gas tank, an alternator, and any needed transformer/induction coils and you'll be all set. Maybe you can start doing some push-ups or something.

      Relatively small yet powerful (enough to do serious damage) lasers have been around for a while now. It's the power supply that tends to be big and bulky. That's the main reason that laser pistols have not replaced traditional firearms. If you want to quickly dump 800-2000+ joules into a distant target, gunpowder and lead remain the easiest way to do it.

      • by Vectronic (1221470) on Wednesday April 20, 2011 @07:33PM (#35886952)

        ...carry around an engine, a gas tank, an alternator...

        You know, I could be wrong of course... but I'm pretty sure it doesn't take the entire engine to power the lasers that run the engine.

        Pretty sure your average household outlet could power all the lasers at once, or even just the car battery, if only for a second or two.

        • by causality (777677)

          ...carry around an engine, a gas tank, an alternator...

          You know, I could be wrong of course... but I'm pretty sure it doesn't take the entire engine to power the lasers that run the engine.

          Pretty sure your average household outlet could power all the lasers at once, or even just the car battery, if only for a second or two.

          Portability seemed like a big concern to GP, considering the uses he was talking about.

          The point was that the possibilities you mention predate the invention of this sparkplug replacement system.

        • by rednip (186217) <rednip@NOSpam.gmail.com> on Wednesday April 20, 2011 @07:59PM (#35887112) Journal

          The reason why this is so novel is not the power of the laser, but it's size, timing and durability. It'll be interesting to see if NASCAR allows it, as efficiency is a big part of winning that closely regulated league.

          From tfa:

          The laser is not strong enough to light the leanest fuel mixtures with a single pulse. By using several 800-picosecond-long pulses, however, they can inject enough energy to ignite the mixture completely.

          A commercial automotive engine will require 60 Hz (or pulse trains per second), Taira says. He has already tested the new dual-beam laser at 100 Hz. The team is also at work on a three-beam laser that will enable even faster and more uniform combustion.

          • by name_already_taken (540581) on Wednesday April 20, 2011 @08:32PM (#35887258)

            The reason why this is so novel is not the power of the laser, but it's size, timing and durability. It'll be interesting to see if NASCAR allows it, as efficiency is a big part of winning that closely regulated league.

            Ummm... The mass-market car manufacturers abandoned carburetors for fuel injection back in 1987, yet NASCAR is still just thinking about using fuel injection maybe in 2012.

            I think you can safely forget about laser ignition systems in NASCAR for a good long time after they're available in regular production cars. While NASCAR cars have been refined over the decades, they are still not using very much technology that would have been unfamiliar to a regular car mechanic in the late 1970s.

            Now, if you'd said Formula 1, then that would make sense.

            • I think you can safely forget about laser ignition systems in NASCAR for a good long time after they're available in regular production cars. While NASCAR cars have been refined over the decades, they are still not using very much technology that would have been unfamiliar to a regular car mechanic in the late 1970s.

              This is kind of a good thing, compared to F1 and Indy. Let the drivers drive (even if it is mostly left turns), rather than a continual $trive for greater tech. Some of the F1 drivers are rebe
            • by Trecares (416205) on Wednesday April 20, 2011 @11:47PM (#35889324)

              Believe it or not, carburetors are better at atomizing the fuel mixture at full throttle conditions compared to injectors.

              Since airflow through a engine at wide open throttle is fairly well known, and easy to meter for, the carb can be adjusted to precisely match that and get the desired air-fuel ratios.

              Injectors can have trouble delivering large quantities of fuel at wide open throttle. When the duty cycle of the injector exceeds about 85-90%, it starts to have problems metering fuel correctly, and the coil starts to overheat. So the typical solution is to drop in larger injectors so a shorter duty cycle can be used.

              The other part of the issue with injectors is the short amount of time they have to deliver and atomize the fuel. The fuel is sprayed against the closed intake valves moments before the intake valves opens. The heat from the valves helps to vaporize the fuel. Since there's only so much heat, and only so much air in the intake port, not all of the fuel may be completely vaporized. The incoming air then has only a bit of time to attempt and vaporize what is left before the valves closes and combustion occurs.

              So why do we use fuel injectors? Because they excel at the thing carbs suck at, part throttle atomization. Injectors can easily meter out a precise amount of fuel determined by the amount of air entering the engine according to it's sensors. A carb has to deal with what it sees across the venturi which isn't as sensitive at part throttle conditions. Toss in the complicated dynamics of the air inside the plenum and it's hard for carbs to precisely meter out fuel.

              • by Kupfernigk (1190345) on Thursday April 21, 2011 @02:51AM (#35890542)
                I have simply hardly ever read such inaccuracies, even in Wikipedia articles (which tend to be edited by automotive fanboys with limited engineering knowledge).

                It may just about be possible for racing, but normal owners would not want to have to readjust the carburetor every time the barometric pressure or temperature changed. And then you have the little problem that a carb will always change the mixture slightly when cornering. It is just not possible to adjust automatically for lateral, rotational and acceleration forces on a pot of gasoline which is being used as the input to a metered jet. Anybody familiar with racing carbs knows that they are a complete pain to set up and keep adjusted.

                Your second point is nonsense. You're just saying "The injector has to be the correct size for the application".

                Third, this is a gross oversimplification. You do not want the fuel completely vaporised. That will cause explosion. Enough fuel has to be vaporised for the ignition to work, but otherwise it has to be atomised - i.e. present as very small droplets - which can then burn at a controlled rate, preventing uncontrollable pressure rise with the risk of gaskets blowing and bearings failing. This problem is common to carburetors and injectors alike. (Diesels do not need any vaporisation at all because they do not have spark ignition.)

                Only your last paragraph is correct. Injectors can do a better job, not only of metering fuel, but also of timing it, stratifying the charge, and ensuring that the mixture around the plugs is ignitable. A carb is basically a crude analog solution to a complex fluidics problem. (Incidentally you contradict yourself - you correctly refer to "atomisation" in that para, whereas you refer to "vaporized" above.)

      • by Jeremi (14640)

        All you'd have to do is find a way to carry around an engine, a gas tank, an alternator, and any needed transformer/induction coils and you'll be all set.

        Sounds to me like they will be sold with such a system already included. All you need to do is add an aimable mirror under the hood... :)

    • by Timmmm (636430)

      None of your applications will be remotely possible with these lasers. This laser only fires an 800 picosecond pulse. It's also going to be impossible to focus at a distance as well as this laser is.

      Besides you can already do all the things you said with existing lasers.

    • by perpenso (1613749) on Wednesday April 20, 2011 @07:42PM (#35887012)

      Cutting and drilling through hardened steel.

      Doubtful for a laser designed for use *inside* an engine. :-)

    • If it burns through steel, it won't be much use in an engine.

  • by dlingman (1757250) on Wednesday April 20, 2011 @06:12PM (#35886234)
    Um - I've looked at spark plugs. They start out nice and shiny, but get gummed up rather quickly. Are the lasers going to need to be strong enough to burn through the carbon buildup as well as igniting diesel/gasoline?
    • Not likely because they'll burn thorough it each time. The beam will always pass out a given point and of course the stuff on it will get all its energy. So it will remain at a steady state.

    • by blair1q (305137)

      That's a good question. Since the scheme seems to involve using more than one low-power laser focussed on a point in space to create one high-power hotspot, AND to pulse it multiple times to build up the heat at that spot, each pulse of of one laser beams doesn't anywhere near the ability to ignite the fuel. So if something does crust over the laser's output hole, it's possible it will never burn off.

      Unless using these things somehow results in random chemicals (gasoline of varying grade and quality; oil;

    • by Daniel_Staal (609844) <DStaal@usa.net> on Wednesday April 20, 2011 @06:26PM (#35886366)

      According to the article, one of the main reasons spark plugs get gummed up is the electrical sparks they are putting out. Electric arcs tend to corrode their endpoints. With a laser, this isn't a problem. Also, the lasers aren't going to try to ignite combustion right in front of them: It's more efficient to ignite it away from them, in the center of the cylinder. Spark plugs can't do that at all.

      Plus, of course, any laser capable of igniting a fuel-air mixture reliably in a few nanoseconds can burn through a bit of soot on the way.

      • Not quite true (Score:5, Insightful)

        by Dcnjoe60 (682885) on Wednesday April 20, 2011 @06:48PM (#35886560)

        According to the article, one of the main reasons spark plugs get gummed up is the electrical sparks they are putting out. Electric arcs tend to corrode their endpoints. With a laser, this isn't a problem. Also, the lasers aren't going to try to ignite combustion right in front of them: It's more efficient to ignite it away from them, in the center of the cylinder. Spark plugs can't do that at all.

        Plus, of course, any laser capable of igniting a fuel-air mixture reliably in a few nanoseconds can burn through a bit of soot on the way.

        If the air fuel mixture is correct, the plugs on a healthy engine won't get gummed at all. If it is too rich or burning oil, it won't matter where the plug or spark originates as the build up occurs everywhere in the combustion chamber (although the rings scrape the wall clean). One only has to pull the heads off an engine to look at the carbon buildup that is no where near the spark gap.

        But the article talks about it being cheaper (okay, more economical). Sparkplugs cost around $3 to $6 each. It seems that a laser strong enough to get through the carbon build up is going to cost more than that. Since plugs now last well over 36,000 miles in new vehicles, it seems trying to improve on an inexpensive technology with a high tech solution is anything but economical.

        • Re:Not quite true (Score:4, Insightful)

          by Daniel_Staal (609844) <DStaal@usa.net> on Wednesday April 20, 2011 @06:57PM (#35886618)

          Depends on:

          A: How much they can improve the fuel efficiency.

          B: How long they last.

          C: How much they cost.

          A $15 laser solution that doesn't improve efficiency but that lasts 100,000 miles is worth the money. If you had one that doubles efficiency but doesn't do last any longer, it can probably cost more and be worth it.

          So far they've got a technology preview that they think meets all the needs of an automotive application. They'll need to design and test an engine that can use it before they'll know the rest, but it's impressive tech so far. It's made from fairly cheap materials, can handle the heat and stress, and can preform a reliable ignition. Is that enough? Maybe, but it looks like enough to be worth trying in a more complete test. Which is all they are trying to do at the moment.

        • by Balthisar (649688)

          100,000 miles is the current norm for a set of spark plugs. Not related to the story, but thought you might want to know that. And while I'm at it, don't change your oil every 3,000 miles either.

          • by Bengie (1121981)

            Co-worker just bought a new Toyota. The book says to only change the oil every 10k miles. cool.

            • Car makers say 'don't change oil so often', Oil makers say 'change oil more often'.

              Is anybody surprised? No automaker has ever recommended 3k miles oil changes.

              • by andydread (758754)
                As someone who has taken apart a quite a few engines I prefer clean oil in my engines thank you very much. The sand paper effect from 10000 miles of dirt buildup is will wear down your engine prematurely. I have seen the difference with my own two eyes and believe me. Its not pretty.
                • by tombeard (126886)

                  Once the clearances have opened up abrasive damage stops. This happens within the first 10K miles. Oil will last practically forever if you change the filter regularly and replace the additive package occasional. I knew a Tribologist that sent samples from his car in for analysis when he did routine testing for his company. He said his company never needed to replace the oil in their large industrial gearboxes (unless something went wrong, like a seal leak or contamination) and by the same criteria he had n

                  • by Grishnakh (216268)

                    The problem, as I understand it with motor oil, is that combustion products from the combustion chamber contaminate the oil. This isn't a factor in gearboxes because there's no combustion going on there, only metal wear, and particles can be filtered easily. Chemical combustion products can't. This is why manual transmissions and differentials don't need their oil changed very often, unlike engines.

        • by Locutus (9039)
          the cost also must include the whole electrical firing system which today means those large coils on top of every plug. There could be a slight weight savings too. I do see your point though since plugs today are good for 40,000 miles or so and cost so little. It will be interesting to follow though and if what is said is true, we should see some nice fuel economy increases. It would be nice if there was an easy way to retro fit if there really are those kinds of efficiency numbers.

          LoB
      • by Mashiki (184564)

        ... It's more efficient to ignite it away from them, in the center of the cylinder. Spark plugs can't do that at all..

        Well no. They don't get gummed up because of the spark, but rather because you're igniting a hydrocarbon. Arcs do corrode their end points, but the quality of a high-end plug these days? Most people anymore won't even need to change their plugs over the life of their car they're that good. 50 years ago, you got 2k miles if that, and you checked the gap every month. 40 years ago it was around 5k miles and you regapped every 6mo. 30 years ago was the first generation of do not gap plugs that would last 3

    • by Anonymous Coward on Wednesday April 20, 2011 @06:46PM (#35886532)

      Diesel engines don't have spark plugs.

    • They start out nice and shiny, but get gummed up rather quickly.

      Then you're doing it wrong. Switch to a hotter heat range. Use platinum or iridium plugs. Make sure your coil is putting out the prescribed voltage. Tune your mixture so it's not too rich. Then, assuming you're not burning oil, at 35,000 miles the plugs should still look clean.

    • by Stargoat (658863) *

      No, because diesel doesn't use spark plugs. That is why it is so much more reliable than petrol. Plus, diesel gets more MPG. Diesel is better than petrol.

  • But how... (Score:3, Funny)

    by blair1q (305137) on Wednesday April 20, 2011 @06:14PM (#35886254) Journal

    Okay. This is really cool. But, how are they going to get the fricken' shark in there?

  • Upon reading the article I saw the mention of leaner fuels. Will this require an alternative fuel mixture to truly improve efficiency or did I interpret this wrong? Thoughts?

    cheers

    • by Anonymous Coward on Wednesday April 20, 2011 @06:24PM (#35886344)

      It expands the distance from stoichiometric that you can go (on the lean side, at least) while still being able to get it to catch on fire correctly while having a good lifespan of your igniter.

      So it's not that the laser "needs" leaner mixtures; it's saying they enable leaner mixtures than current (mass-market) spark plug technology. And for steady-state cruising, that could be a great way to cut down on NOx emissions. (Not sure if it will reduce fuel consumption.) Of course, I thought the catalytic converters were already digesting all the NOx, so, I'm not sure why this is super-awesome...

    • If by 'fuel mixture' you mean 'ratio of air to fuel', yeah, you'd need a new mix to get the most benefits.

      If by 'fuel mixture' you mean switching out gasoline for something else, probably not.

    • No, 'lean' just refers to the mix of fuel and air. You put less fuel into the cylinder each cycle, and the energy of the fuel is used more efficiently. So you might end up with a 2000cc engine which performs like a 1500cc engine but consumes fuel like a 1300cc engine - except that you have the option to run richer (more fuel per cycle) if you need to, getting 2000cc performance at 2000cc fuel consumption (and also without the reduction in nitrogen oxide emission.)

      I am not an automotive engineer, feel free t

    • by nomel (244635)

      With a rich mixture, the flame from ignition moves slower [innovatemotorsports.com] so the pressures after TDC (top dead center) are lower. With a lean mixture, they move so quickly that the pressure and heat from it can be sufficient to detonate [alexap.com] the fuel. Running leaner gives better fuel efficiency (nice graph) [alexap.com], but also increases your chance of detonation under power (high cylinder pressures).

      I *think* that by using a laser system, you don't have a spark plug sticking in the cylinder with sharp edges that would usually get very ho [wikipedia.org]

      • by AK Marc (707885)
        Anything the fuel touches can set off the detonation. So the "ideal" would be to spray the fuel directly in and ignite it before it touched anything. That will only work if running lean. Why? Because you want as close to perfectly mixed fuel and air before you ignite the mixture. If you have that goal, you must touch the edges with fuel. But if you work out a way to put a cloud of fuel 80% the size of the combustion chamber perfectly mixed in that 80% and touching nothing until the laser ignites it fr
    • By "leaner fuel mixtures" they're not saying that you have to change the gasoline itself - you just inject less of it.

      Even without running leaner, yes, this can improve efficiency: it can ignite the fuel closer to the center of the combustion chamber, which makes for a better burn. It might also ignite a longer path of the fuel, resulting in a quicker burn without detonation. You retard timing a little bit, and then do a quick burn to bring up pressure right at the best moment. This is already done on so

    • My 1980 Honda Civic used a 3 barrel carburetor to produce one (tiny) rich air/fuel mixture and two channels of lean mixture. The rich was fed by a separate valve to a tiny pre-ignition chamber that the spark plug lived in, and the rest of the 336cc cylinder was filled with lean mixture.

      That engine was the last one, by any major manufacturer, to pass US emissions standards without a catalytic converter - it was inherently clean burning enough to meet the 1980 standards without one. It was also rather effic

  • You thought replacing flaky early-run coil-packs was expensive. What does a replacement laser-ignitor cost?

    Is it susceptible to fouling and such? Can it be cleaned in such cases? If your engine pings does it destroy the laser? etc.

    I'm not afraid of change or anything, but igntion systems have come a long way since the model T. All you need to change now is the plugs, no more rotor, cap, points, condenser. It's a nice reliable system.

    Be curious to see this though.

    • by icebike (68054)

      I'd like to see the data on improved fuel consumption.

      I don't see why laser ignited fuel-air mixture will be all that much cleaner than a spark ignited mixture.
      The only possible source of improvement would be that a laser could ignite fuel over its entire path, rather than at a single point, making for a more even combustion pattern.

      • Re:Can't see it. (Score:4, Insightful)

        by blair1q (305137) on Wednesday April 20, 2011 @06:30PM (#35886402) Journal

        TFA talks about that.

        The shape of the flame makes a difference in how well the fuel burns, and in how efficiently the piston transduces the pressure curve into mechanical motion. Same reason for differing piston and head shapes.

        You don't really want fuel to explode, you want it to burn quickly and in the right shape. Apparently, starting the flamefront from a single point is not super-efficient even if you have control of the shape of the cylinder.

      • by xMrFishx (1956084)
        I wonder if this would also reduce the electrical noise on the car circuits. That would be good news for in car electronics.
      • The only possible source of improvement would be that a laser could ignite fuel over its entire path, rather than at a single point, making for a more even combustion pattern.

        Not a good idea. This is essentially what detonation (pinging) is. You need a specific spot of origin, then a progressive burn across the combustion chamber. This yields a slow gentle pressure wave (relatively speaking) on the power stroke, rather than a massive, parts-breaking kick.

        • by icebike (68054)

          Not a good idea. This is essentially what detonation (pinging) is. You need a specific spot of origin, then a progressive burn across the combustion chamber. This yields a slow gentle pressure wave (relatively speaking) on the power stroke, rather than a massive, parts-breaking kick.

          Hmmmm, maybe you could look at Blair1Q's post [slashdot.org] and TFA
          and explain to both of them that what they invented won't work.

          Lasers also improve efficiency. Conventional spark plugs sit on top of the cylinder and only ignite the air-fuel mixture close to them. The relatively cold metal of nearby electrodes and cylinder walls absorbs heat from the explosion, quenching the flame front just as it starts to expand.

          Lasers, Taira explains, can focus their beams directly into the center of the mixture. Without quenching, the flame front expands more symmetrically and up to three times faster than those produced by spark plugs

          • by aXis100 (690904)

            With a super fast laser initiated frame front, I imagine they'll adjust the timing closer too, or ever after top dead center. That will stop the parts-breaking kick.

            The reason pinging is so bad is that it happens whilst the piston is still on the upstroke.

        • by Locutus (9039)
          the focal point will get you combustion at a point and TFA talks about this.

          LoB
          • by Locutus (9039)
            ok, it mentioned the ability to set a combustion point and moving it to an optimal position. to me that said focal point.

            LoB
    • You thought replacing flaky early-run coil-packs was expensive. What does a replacement laser-ignitor cost?

      From Rain Man:
      Doctor: Ray, do you know how much a candy bar costs?
      Raymond: 'Bout a hundred dollars.
      Doctor: Do you know how much one of those new compact cars costs?
      Raymond: 'Bout a hundred dollars.
      Doctor: Do you know how much a replacement laser-ignitor costs?
      Raymond: 'Bout a hundred dollars.

    • by nabsltd (1313397)

      All you need to change now is the plugs, no more rotor, cap, points, condenser. It's a nice reliable system.

      Yeah, at this point unless spark plugs are responsible for greatly increased fuel use, then the cost of switching to something else has to be close to zero to make a change worthwhile.

      I think I spent about $300 total for spark plugs (including the labor for somebody else to replace them) in the 10 years I had my last vehicle (an 8-cylinder, BTW).

  • I remember an article from.. oh... 25 years ago in Popular Mechanics or similar saying similar things about plasma jet spark plugs. Igniting a larger portion of the mixture farther from the head, etc.

    Now it's lasers. Ok.. if the laser is collimated before it leaves the 'plug', wouldn't it ignite the air/fuel mix right at the plug tip just like current spark plugs do? If there's a lens focusing the laser to an ignition point farther from the tip, then is the laser light concentrated enough to burn off any re

    • Re: (Score:2, Insightful)

      by geekoid (135745)

      exfept here's the thing:
      You can buy a LASER that can cut steel, right now. As a consumer.

      "...wouldn't it ignite the air/fuel mix right at the plug tip just like current spark plugs do?"
      Nope

      "so wouldn't a laser be overkill?"
      also, Nope.

      "Color me skeptical about the potential improvements to be had from using lasers instead of spark plugs."
      How about if I just color you ignorant?

    • by cbhacking (979169)

      It's not one laser firing one beam that ignites the fuel. Instead you use multiple lasers firing in a pattern that intersects at one point in the middle of the cylinder. No single beam is powerful enough to ignite the fuel, so the situation you mention doesn't occur. It requires a different cylinder design and different fuel/air ratio for maximum efficiency, but that maximum efficiency is higher than a spark plug ignited engine can get.

    • by Grishnakh (216268)

      I remember an article in an automotive engineering trade magazine about 20 years ago which showed an experimental new engine that used electric solenoids to actuate the valves, rather than camshafts. By having computer-driven valves, the engine could have any arbitrary valve timing, without any complicated mechanical components. Embedded computers (needed for something like this) have come a long way since 1991, but I still haven't seen any solenoid-driven valves since then.

  • Or... (Score:4, Interesting)

    by jensend (71114) on Wednesday April 20, 2011 @06:58PM (#35886634)

    you could just go diesel and skip this business entirely. More than half of the vehicles sold in Europe are diesel; it just makes more sense fuel-economy wise. We need to get with the program on this side of the pond.

    I'm still waiting for my VW XL1...

  • by Tumbleweed (3706) * on Wednesday April 20, 2011 @07:01PM (#35886658)

    I bought a diesel. My 2001 VW Jetta TDI gets about 45mph highway. No spark plugs, no lasers, no problem. *shrug*

    • by ArcCoyote (634356)

      Only 45 MPH? I'd be afraid to take that out on the highway.

      • by Tumbleweed (3706) *

        Ha, oops, 45mpg. That's with a 10+ year-old car, too, which is pretty nice. Too bad it's loud as hell.

    • by mirix (1649853)

      My 2001 VW Jetta TDI gets about 45mph highway.

      I would hope it goes faster than that. :p

      A few of my relatives have TDIs, great little engines, excellent mileage.
      I opted for the gas fueled GTI though... double the power and starts better in our -40 climate. At the cost of half the mileage though. Way it goes I guess.

      If I had a longer commute or travelled more, I'd definitely have gone with the diesel though.

      • by Tumbleweed (3706) *

        I keep wondering how efficient a diesel _series_ plug-in hybrid would be. Diesels are, by their very nature, far more efficient than gasoline engines, and thus make great engines for generators. I'm wondering if natural gas is more efficient yet for a generator? Gas turbine? A series plug-in hybrid with a generator using whatever the most-efficient engine *for a generator* seems like a good idea. Now that the unsprung weight issue has been solved and we can use wheel hub motors for some very nice weight dis

  • by theManInTheYellowHat (451261) on Wednesday April 20, 2011 @07:10PM (#35886750)

    The problem that needs to be solved is the reason for the spark. The reason for the spark is the need for the ignition of fuel. Switching to laser beam driven electron motors would be crazy cool (or whatever other cool use there is for a laser in an electric motor if there is one). "Fixing" something that is not broke with a gadget that needs to bought (and thus sold) seems like a great idea for an infomercial, not a solution to the worlds problems.

  • From the The University of Tennessee Space Institute:
    "Although laser ignition offers advantages for most combustion sources, its greatest potential exists for jet-engine gas-turbine combustors."

    http://cla.utsi.edu/Research/Fluid_Physics/Laser_Induced_Ignition.htm [utsi.edu]

  • I think there is (at least) one error in the article.

    Don't lean mixtures produce /more/ NOx? Excess oxygen on the hot gasses oxidize anything they can find, which is the 70% nitrogen in the air?

    Lean mixes produce NOx. Rich mixtures produce CO (Not enough oxygen to completely burn all the carbon.). Correct mixes produce both (although not as much!)

    Of course, laser ignition may well enable leaner mixes, probably using more Exhaust gas recirculation, while not producing excess NOx, which is a good thing, certa

    • by PPH (736903)

      Higher temperature combustion produces more NOx. Higher temps are produced by higher compression. Hence no more high compression (unboosted) engines.

      Lean burn is good. Honda (and others) used it in their CVCC engines, where a small region of rich mixture is ignited by a spark and that in turn ignites a larger charge of lean mixture.

      One of the limitations of lean mixtures has been the ability of a spark to ignite it (hence all the fancy CVCC, vortex, stratified charge systems used by various manufacturers)

  • I misread the title to read "Lasers to replace fins on sharks". That's it. I'm giving up surfing.
  • by rgviza (1303161)

    Have a small issue with the text of the story; sparkplugs don't power engines, gasoline vapor and oxygen do. The spark plugs ignite the air/fuel mixture and the resulting explosion forces the pistons down, powering the engine..

    A more correct first sentence would be "For more than 150 years, spark plugs have been used in engine ignition systems to start the combustion cycle."

    • by rgviza (1303161)

      As well, 125 years would be more correct. Ironically 4 cycle engines 1876 were invented before 2 cycle (in 1889), which are actually simpler. The 2 cycle was invented to get around infringing on the 4 cycle patents. So much for patents fueling innovation....

      Ignition devices are used for more than just gasoline engines.

Never tell people how to do things. Tell them WHAT to do and they will surprise you with their ingenuity. -- Gen. George S. Patton, Jr.

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