Laser Spark Plugs - Sparking in an efficient way

Electric and hybrid cars are making inroads into automobile scene today. Still, internal combustion (IC) engines are likely to remain in widespread use for some more time. Efforts to make IC engines more efficient, and ecofriendly are on the way, but one possible casualty could be the 150 year old spark plug! Researchers from Japan's National Institutes of Natural Sciences (NINS) are creating laser igniters that could one day replace spark plugs in cars. These laser gadgets promise to improve fuel economy and reduce emissions of smog causing nitrogen oxides (NOx). It ignites an engine’s air-fuel mixture more efficiently and further down within the cylinder, burning more air and less fuel.

Traditional spark plug is an electrical device that works by igniting the compressed fuel nearest to the cylinder head with jolts of high
voltage electricity. The controlled mini-explosion that results, pushes the piston down.

For the engines to produce less NOx, the plugs will have to produce higher-energy sparks. While this is technically possible, the
voltages involved would burn out the electrodes of spark plugs quite quickly. Laser igniters on the other hand, could ignite leaner mixtures without self-destructing because they don't have electrodes. The NINS scientists also address another limitation of spark plugs - the fact that they only ignite the area of the air-fuel mixture closest to them (the top), with much of the heat of the explosion being absorbed by the metal cylinder walls before it can reach down to the piston. Lasers, by contrast, could focus their beams into the middle of the column, from which point the explosion would expand more symmetrically - and reportedly up to three times faster than one triggered by a spark plug.

Additionally, engine timing could be improved, as lasers can pulse within nanoseconds, while spark plugs require milliseconds.