Laser Spark Plugs: The Internal Combustion Engine’s Last Bid For Relevance?

Fitting a gasoline-powered car engine with laser spark plugs sounds like sci-fi, but it may stave off the electric revolution a little while longer.

spark plugs


Fitting a gasoline-powered car engine with frikkin’ laser spark plugs may seem like one sci-fi step too far, but since it improves the combustion and cleans-up the exhaust, it may be the gas engine’s last gasp before the electric revolution comes.

The design of the spark plug really hasn’t changed very much since the gasoline engine was invented–they’re a device that creates an electric spark across a very precise small gap to ignite the fuel mixture in each cylinder, and apart from improving their materials and reliability there’s not much you can do to tweak that.

The problem with spark plugs is that they’re not particularly good at their raison d’être. They just don’t ignite the fuel-air mixture efficiently, particularly as they age. Incomplete combustion can result, which means that unspent fuel, combustion by-products, and higher levels of nitrogen oxides (a key component in smog) are spat out in the exhaust–which also lowers your car’s fuel efficiency. Scientists have long known lasers could do a better job, because lasers can do a better job at most everything: They can be more precisely controlled in timing and ignition levels and they don’t suffer from wear due to electrical arc “pitting” like traditional spark plugs do. But squeezing a laser powerful, sturdy and reliable enough into your engine hasn’t been possible.

But a team from Japan’s National Institute of Natural Sciences is set to demonstrate a laser-plug breakthrough at the upcoming international conference on Lasers and Electro-Optics, and it’s a doozy: They’ve perfected a laser that makes heavy use of strong ceramic materials, which can better withstand the temperatures and pressures. For you spark plug nerds, here are the details (non spark-plug nerds may skip to the next paragraph): It’s actually a complex composite device, made of two yttrium-alluminium-gallium lasing segments, one doped with neodymium, the other with chromium. It’s only 9mm across, and 11mm long which makes it perfectly sized to fit inside even the smallest engine blocks. And unlike the microsecond precision of conventional spark plugs, the team notes the lasers can be triggered with nanosecond accuracy and can even be pulsed to ensure the most efficient combustion–it also focuses its ignition energy into the center of the fuel-air mix, unlike spark plugs–which ignite at the top–ensuring even cleaner burning. The team is working with a “big” spark-plug manufacturer and a member of the Toyota group, so the tech may arrive in cars sooner than you may think.

Why’s this so important? Because by adding such a high-tech tweak to an age-old inefficient design, the research may actually clean up the exhaust of the internal combustion engine–giving the technology a slightly extended lease of life. We can’t quite seem to quit the dirty engine, yet. The all-electric revolution is happening all around us, slowly, but consumers aren’t exactly rushing to embrace it with open arms. Pretty much everyone still drives a gas-powered car, and even if they’re considering going green (to deal with rising gas prices) they’ll probably opt for a hybrid… which still relies on a gas-burning engine. Laser-powered spark plugs may be one way to incrementally clean up our dirty cars before the government finally forces us to get clean from our gasoline-powered addiction.

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Image via Flickr user asgw.

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