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Lasers To Replace Sparkplugs In Engines?
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."
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...
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.
'Sensible' is a curse word.
Remote ignition of fires or detonation of explosives.
Your comment was duly noted and a shiny black DHS van was dispatched to your location.
Catalytic converters are expensive and relatively heavy. Take them out and you get a cheaper, lighter car. Cheaper is always good, and lighter translates to better handling and better fuel economy. Probably nothing major, but every little bit helps.
'Sensible' is a curse word.
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.
It is a miracle that curiosity survives formal education. - Einstein
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.
Putting moderation advice in your
One of the benefits and drawbacks of running lean is the mixture burns hotter. This produces more NOx, not less. I'm not sure what the article is going on about.
It didn't say it in the article, but this is a different type of laser than the cutting kind. The idea behind these is to use the laser to create a spark wherever you focus it. The laser excites the molecules in the mixture and eventually ionizes enough of them to cause breakdown (the spark). The plasma from this spark then heats the mixture and causes ignition. The advance this group made was that they managed to make a small enough semiconductor laser capable of making such a spark that it has the potential to go into mass production...theoretically. Probably another of those advances that will make its way into high end cars at first and, hopefully, work its way down from there once it gets cheaper and gas continues to get expensive enough to make the better efficiency worth the cost.
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.)
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