Start up a modern car with a gasoline engine and you’re almost surely making use of a spark plug, which sends a high-voltage electrical spark to ignite the gas. (Diesel engines don’t require spark plugs due to their very high compression ratios.) But Japanese researchers have come up with a tech innovation that could supplant spark plugs as we know them: Small YAG lasers which could more precisely ignite fuel. Not only does this sound cool, but it could lead to higher efficiency, more eco-friendly combustion.
While laser ignition wouldn’t do much for carbon dioxide emissions, researchers say that by virtue of causing the engine to burn more air and less fuel, it could lead to “significantly smaller” emissions of nitrogen oxides (NOx), a major component of smog and acid rain.
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, [Takunori] 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.
Equally important, he says, lasers inject their energy within nanoseconds, compared with milliseconds for spark plugs. “Timing — quick combustion — is very important. The more precise the timing, the more efficient the combustion and the better the fuel economy,” he says.
(ScienceBlog via HN. Title pic [mockup] via Gizmag.)
