<p>In the past, lasers strong enough to ignite an engine's air-fuel mixtures were too large to fit under an auto hood. <br /><br />Conventional spark plugs pose a barrier to improving fuel economy and reducing emissions of nitrogen oxides (NOx), a key component of smog, said Taira, according to the institute's statement. <br /><br />Spark plugs work by sending small, high-voltage electrical sparks across a gap between two metal electrodes. The spark ignites the air-fuel mixture in the engine's cylinder, producing a controlled explosion that forces the piston down to the bottom of the cylinder, generating the horsepower needed to move the vehicle.<br /><br />Engines make NOx as a byproduct of combustion. If engines ran leaner - burnt more air and less fuel - they would produce significantly smaller NOx emissions. Spark plugs can ignite leaner fuel mixtures, but only by increasing spark energy. <br /><br />Unfortunately, these high voltages erode spark plug electrodes so fast, the solution is not economical. Conversely, lasers, which ignite the air-fuel mixture with concentrated optical energy, have no electrodes and are not affected. <br /><br />Equally important, Taira 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. <br />Lasers promise less pollution and greater fuel efficiency, but making small, powerful lasers has, until now, proven hard. <br /><br />These findings will be presented at the Conference on Lasers and Electro Optics scheduled in Baltimore, US, in the first week of May.</p>
<p>In the past, lasers strong enough to ignite an engine's air-fuel mixtures were too large to fit under an auto hood. <br /><br />Conventional spark plugs pose a barrier to improving fuel economy and reducing emissions of nitrogen oxides (NOx), a key component of smog, said Taira, according to the institute's statement. <br /><br />Spark plugs work by sending small, high-voltage electrical sparks across a gap between two metal electrodes. The spark ignites the air-fuel mixture in the engine's cylinder, producing a controlled explosion that forces the piston down to the bottom of the cylinder, generating the horsepower needed to move the vehicle.<br /><br />Engines make NOx as a byproduct of combustion. If engines ran leaner - burnt more air and less fuel - they would produce significantly smaller NOx emissions. Spark plugs can ignite leaner fuel mixtures, but only by increasing spark energy. <br /><br />Unfortunately, these high voltages erode spark plug electrodes so fast, the solution is not economical. Conversely, lasers, which ignite the air-fuel mixture with concentrated optical energy, have no electrodes and are not affected. <br /><br />Equally important, Taira 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. <br />Lasers promise less pollution and greater fuel efficiency, but making small, powerful lasers has, until now, proven hard. <br /><br />These findings will be presented at the Conference on Lasers and Electro Optics scheduled in Baltimore, US, in the first week of May.</p>