The Bright Future of Laser Ignition | Argonne National Laboratory

June 13, 2017

Argonne’s laser-ignition research is entering the limelight

Lasers have fascinated scientists for nearly 60 years as their bright rays revolutionized entire industries - from music and medicine to fashion and retail. Now Argonne engineers are using lasers to try to transform the energy industry by replacing spark plugs with lasers, which can improve the efficiency of modern engines while reducing harmful emissions.

Argonne engineers examine and test many types of advanced ignition systems, but their research into laser ignition goes deeper. Starting more than 10 years ago, Argonne engineers Sreenath Gupta and Bipin Bihari applied new technologies to laser ignition that led to two patents.

Argonne’s research shows promise for stationary natural gas generators. “As engine manufacturers strive to improve fuel efficiency and reduce emissions, they increasingly rely on leaner fuel-air mixtures and higher pressures,” said Gupta. At these extremes, spark plugs tend to fail and require much more maintenance.

To solve these challenges, Argonne engineers are looking to laser igniters, which are more reliable and durable. The initial flame triggered by a laser is much larger than with a spark plug, which allows the system to better handle the harsh conditions of modern engines.

In 2004, Gupta, Bihari, and their colleagues discovered the potential of laser ignition to cut nitrogen oxide (NOx) emissions up to 70% or boost engine efficiency by 3%. Yet the setup was impractical. Large desk-sized lasers needed mirrors to direct the beams into an engine’s combustion chamber.

Lasers are also more dependable because they have no physical parts inside the combustion chamber. Argonne engineers simply aim lasers through a sapphire lens to ignite the mixture of fuel and air. The lack of maintenance is especially important for large stationary engines that power generators for the electric grid, which are offline for days to replace damaged spark plugs.

As lasers evolved and shrunk, Gupta and Bihari switched to laser igniters nearly as small as spark plugs. With this breakthrough, Gupta and Bihari successfully tested laser ignition in an entire six-cylinder engine.

“No one else has done this,” said Gupta. The latest laser igniter “can withstand engine heat and vibration and is almost ready for production,” he said. Indeed, Gupta and his team have partnered with several businesses that are taking the next steps towards production and commercialization.