Lasers to replace spark plugs?

Researchers in the UK are replacing conventional spark plugs with lasers, significantly reducing carbon emissions.

If early reports are right, it could be one of recent automotive development's big win-wins. The use of sharply focused laser beams into combustion chambers could open up a whole new set of engine efficiencies.

Firstly, the engine fires up better in the cold and the wet. Once it's started, better ignition efficiency gets it up to optimum running temperature faster, cutting CO2 emissions. All from a system that demands a lower electrical input from battery or alternator than existing systems.

The team behind this laser-based ignition system hails from Liverpool University, led by Dr Tom Shenton. With help from Ford the team has developed a new ignition system which uses focused beams of laser light to ignite the fuel.

It uses optical fibre to carry laser light to the cylinder, at which point it's narrowed through a lens like sunlight through a magnifying glass, into a pinpoint generating enough heat to fire the fuel mixture.

The use of focused light overcomes one of the major problems confronting traditional spark plug systems: the static placement of the spark at one end of the cylinder. The spark is often not the optimum spot for it in relation to the injected fuel, compromising the efficiency of the combustion process.

This is overcome, to a point, by the use of twin-spark systems. But that serves only to lessen the plug system's limitations.

"Lasers can be focused and split into multiple beams to give multiple ignition points, which means it can give a far better chance of ignition," Shenton told UK press.

"So it can boost engine performance when it's cold -- that's when engines produce around 80 percent of exhaust emissions. And it burns more stably."

Which translates into greater combustion efficiency as it needs less fuel per bang, which means it's also more economical.

The project has attracted £200,000 ($A400,000) in ongoing development funding from the Carbon Trust, the non-government organisation set-up to accelerate the UK's transformation to a low-carbon economy. Robert Trezona, R&D head at the trust, pointed out another potential benefit: "It can also be used in mixed fuel engines such as biofuels."

Laser light reflections from inside the chamber can be collected and translated into data to help the EMS optimise the intensity and placement of ignition. This opens the way for complex adjustment of air and fuel intake in real time, potentially allowing engines to run on multiple fuels without compromising efficiency.