Despite all the attention given to electric vehicles, the venerable gasoline-based internal-combustion engine (ICE) is still very much with us, and it appears it will be for a long time. The air-fuel ignition subsystem of today for the gasoline-fueled ICE vehicle is a highly refined, computer-controlled, fuel-injected system incorporating many significant technical advances. It’s far more efficient and dynamically adaptable compared to the basic, simpler carburetor-based system with mechanical distributor and fixed ignition timing that was standard not that many years ago. Nonetheless, additional tangible gains are possible with a radically different approach that uses laser ignition (LI) instead of the conventional electric spark plug (ESP) technique.
Why even consider a laser spark plug (LSP) and laser ignition? The LSP eliminates the need for the protruding electrode of the regular spark plug, thus enhancing the combustion area. Also, the laser’s energy can be directed at different locations in the cylinder to ignite the gas-air mixture, which may further improve performance. Finally, multiple laser beams are able to be directed into the cylinder for more complete combustion.
To demonstrate this, a research team composed of three Romanian organizations has configured and tested a standard Renault engine using laser ignition, achieving improvements in fuel efficiency as well as reduction in exhaust pollutants – see figure 1.