What am I talking about? Laser spark plugs.
Quite of bit of progress has been made since I last covered it about 4 years ago or so, with the size of the laser units now being slightly larger than traditional spark plugs. One of the advantages of laser plugs versus traditional spark plugs? More efficient combustion.
Another plus of laser ignition is that there can be more than a single ignition point within the cylinder, which in turn gives better control over combustion.
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. Unfortunately, these high voltages erode spark-plug electrodes so fast, the solution is not economical. By contrast, lasers, which ignite the air-fuel mixture with concentrated optical energy, have no electrodes and are not affected.
These lasers also improve efficiency, according to their creators. 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, 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.
While I don't expect to see sets of these new laser plugs in the local auto parts store any time soon, it does show us research and development of systems that will increase the efficiency of internal combustion engines continues.