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Lasers To Replace Sparkplugs In Engines?

Posted by samzenpus on 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."

9 of 351 comments (clear)

  1. I can't wait for the hacks by plover · · Score: 4, Insightful

    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.

    --
    John
    1. Re:I can't wait for the hacks by Vectronic · · Score: 3, Insightful

      ...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.

  2. Re:Can't see it. by blair1q · · Score: 3, Insightful

    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.

  3. Re:Keeping the emitter clean... by Anonymous Coward · · Score: 5, Insightful

    Diesel engines don't have spark plugs.

  4. Not quite true by Dcnjoe60 · · Score: 4, Insightful

    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.

    1. Re:Not quite true by Daniel_Staal · · Score: 3, Insightful

      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.

      --
      'Sensible' is a curse word.
  5. Re:Where are plasma plugs? by geekoid · · Score: 1, Insightful

    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?

    --
    The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
  6. I got rid of spark plugs a different way entirely. by Tumbleweed · · Score: 3, Insightful

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

  7. A laser designed for use *inside* an engine ... by perpenso · · Score: 3, Insightful

    Cutting and drilling through hardened steel.

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