Lasers could replace spark plugs

24 April 2011 Last updated at 00:36 GMT By Jason Palmer Science and technology reporter, BBC News Two or three lasers are focused to ignite fuel in more than one place Car engines could soon be fired by lasers instead of spark plugs, researchers say.

A team at the Conference on Lasers and Electro-Optics will report on 1 May that 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 mixture.

The team is in discussions with a spark plug manufacturer.

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.

Continue reading the main story

In the past, lasers that could meet those requirements were... big, inefficient, and unstable”

End Quote Takunori Taira National Institutes of Natural Sciences, Okazaki But only with the advent of smaller lasers has the idea of laser-based combustion become a practical one.

Ceramic powders

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.

Spark plugs only ignite the fuel mixture very near the spark gap

"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.

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

View the original article here

This post was made using the Auto Blogging Software from WebMagnates.org This line will not appear when posts are made after activating the software to full version.

Egypt's army to replace governors

10 April 2011 Last updated at 07:06 GMT Protesters remained in Tahrir Square despite an army threat to use force to remove them Egypt's interim military government has said it will remove some provincial governors appointed by former President Hosni Mubarak.

The move is an apparent concession to protesters who want Mr Mubarak and his allies tried for corruption.

It follows an army move on protesters in Cairo's Tahrir Square on Saturday in which at least one person was killed.

The military has said it will use force to clear the square "to ensure life goes back to normal" in Egypt.

Dozens of people were also injured in the violence in Tahrir Square early on Saturday as the army tried to enforce an overnight curfew.

They suffered gunshot wounds but the army denies using live rounds.

The violence came after hundreds of thousands of people protested in Tahrir Square on Friday, demanding the prosecution of Mr Mubarak for corruption.

More protesters returned to the square later on Saturday and remained overnight.

On Sunday morning a few hundred protesters were in the square, which was sealed off with barbed wire and closed to the usually busy traffic of the beginning of Egypt's work week.

Army threat

Tensions have been growing between the military, who took control after Mr Mubarak's downfall in February, and protesters calling for speedier reforms.

Divisions have also emerged within the protest movement that forced Mr Mubarak's resignation, says the BBC's Yolande Knell in Cairo.

Some are calling for the resignation of the head of the ruling military council, Field Marshal Mohamad Hussein Tantawi, who is Egypt's interim ruler.

He was defence minister under Mr Mubarak and was very close to the former president.

Others in the protest movement fear further antagonism with the military will cause more problems for Egypt ahead of elections and a transition to civilian rule planned for later in the year, our correspondent says.

The military's move to replace a number of Mubarak-appointed provincial governors was one of the demands of protesters.

Many among the protest movement believe the military figures now overseeing political transition are protecting Mr Mubarak and his allies.

On Saturday, a general said the army was "ready" to use force to clear the square and allow normal life to resume.

"Tahrir Square will be emptied of protesters with firmness and force to ensure life goes back to normal," Major General Adel Emarah, of the military council, told a news conference.

The army had maintained a generally neutral role in the earlier mass demonstrations.

View the original article here

This post was made using the Auto Blogging Software from WebMagnates.org This line will not appear when posts are made after activating the software to full version.