Lasers to replace spark plugs in cars

Car engines could soon be fired by eco-friendly and energy-efficient lasers.

London: Car engines could soon be fired by environment-friendly and energy-efficient lasers, replacing the 150-year-old spark plugs, researchers have claimed.

Researchers said they have designed lasers that could ignite the fuel/air mixture in combustion engines.

The approach would increase efficiency of engines, and reduce their pollution, by igniting more of the fuel/air mixture, a team at the Conference on Lasers and Electro-Optics will report on May 1.

The team is in discussions to commercialise the technology with Denso, a major automobile component manufacturer, BBC reported.

The idea of replacing spark plugs - a technology that has changed little since their invention 150 years ago – with lasers is not a new one.

Spark plugs only ignite the fuel mixture near the spark gap, reducing the combustion efficiency, and the metal that makes them up is slowly eroded as they age.

But only with the advent of smaller lasers has the idea of laser-based combustion become a practical one.

A team from Romania and Japan has now demonstrated a system that can focus two or three laser beams into an engine`s cylinders at variable depths.

That increases the completeness of combustion and neatly avoids the issue of degradation with time.

However, it requires that lasers of high pulse energies are used; just as with spark plugs, a great deal of energy is needed to cause ignition of the fuel.

"In the past, lasers that could meet those requirements were limited to basic research because they were big, inefficient, and unstable," said Takunori Taira of the
National Institutes of Natural Sciences in Okazaki, Japan.

"Nor could they be located away from the engine, because their powerful beams would destroy any optical fibres that delivered light to the cylinders."

The team has been developing a new approach to the problem: lasers made of ceramic powders that are pressed into spark-plug sized cylinders.

These ceramic devices are lasers in their own right, gathering energy from compact, lower-power lasers that are sent in via optical fibre and releasing it in pulses just 800
trillionths of a second long.

Unlike the delicate crystals typically used in high-power lasers, the ceramics are more robust and can better handle the heat within combustion engines.