PATENTS for the spark plug go as far back as the late 1890s. But it was Robert Bosch's invention of the high-voltage spark plug in 1902 that lead to the widespread adoption of the internal combustion petrol engine.
Now, the humble spark plug may be on its way to the history books, with scientists in the UK and engineers at Ford developing an ignition system which uses focused beams of laser light to ignite fuel, rather than an arc of electricity from a spark plug.
The team behind the project says the technology is more reliable and efficient than the spark plug, and Ford plans to begin using the new ignition system in its top-shelf models within the next two to three years.
With the new technology, the spark plug in an engine is replaced by a laser, which sends its light along thin optical fibres into the engine's cylinders, where lenses focus the beam into a pinprick of light that ignites fuel after it enters the combustion chamber.
The laser fires more than 50 times per second when the engine is running at 3000rpm, and requires less power than regular spark plugs.
Dr Tom Shenton, lead engineer in the project, run by Liverpool University in the UK, told The Telegraph: "We are running engines everyday in our laboratory with this system now and our ultimate objective is to have it inside cars driven by consumers.
"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.
"This can really improve the performance of the engine when it is cold, as this is the time when around 80 per cent of the exhaust emissions are produced and the engine is at is least efficient.
"The laser also produces more stable combustion so you need to put less fuel into the cylinder."
Dr Shenton said that the laser can also reflect its light back from inside the cylinder, allowing the car's ECU to gather and analyse data about the engine's performance, and take action such as adjusting air and fuel automatically to improve and maintain the best possible performance and efficiency.
A spokesman for Ford told The Telegraph: "Ford, like all vehicle manufacturers, is obliged by European legislation to reduce emissions and our work in this area is led by Ford's UK R&D centre in Essex.
"This collaboration with the University of Liverpool is part of that effort, with Ford contributing in kind, with engineering time and equipment use, as well as financially."
Liverpool University and Ford aren't the only ones working on laser plug technology, however, with Colorado University in the United States taking up the challenge back in 2006.
The engineers at CU discovered that the optical fibre the laser light travels along would need to be significantly stronger than regular optical fibre, which disintegrates quickly because of the massive energy passing through it.
The university has since patented a new type of optical fibre, 700 micrometres in diameter and filled with helium.
As with Liverpool University's system, laser light is fired along the fibres into the engine cylinders, where a lens focuses the intense light onto a specific spot. An electrical breakdown of gas inside the cylinder then occurs, generating a plasma spark which ignites the fuel.
Unlike the team at Liverpool, Colorado Univesity's project is aimed at large-bore gas engines manufactured by companies such as Caterpillar and Cummins for use in power generation and natural-gas pumping.