Toyota Yaris Forums - Ultimate Yaris Enthusiast Site
 

 


 
Go Back   Toyota Yaris Forums - Ultimate Yaris Enthusiast Site > Members Area > Off-topic / Other Cars / Everything else Discussions
  The Tire Rack

Reply
 
Thread Tools Display Modes
Old 04-24-2011, 03:27 PM   #1
Altitude
 
Altitude's Avatar
 
Drives: '08 LB MT Bayou
Join Date: Oct 2008
Location: Colorado
Posts: 1,701
Laser plugs? - Awesome

laser-to-replace-spark-plugs-in-combustion-engines

WASHINGTON, April 20—For more than 150 years, spark plugs have powered internal combustion engines. Automakers are now one step closer to being able to replace this long-standing technology with laser igniters, which will enable cleaner, more efficient, and more economical vehicles.

In the past, lasers strong enough to ignite an engine’s air-fuel mixtures were too large to fit under an automobile’s hood. At this year’s Conference on Lasers and Electro Optics (CLEO: 2011), to be held in Baltimore May 1 – 6, researchers from Japan will describe the first multibeam laser system small enough to screw into an engine’s cylinder head.

Equally significant, the new laser system is made from ceramics, and could be produced inexpensively in large volumes, according to one of the presentation’s authors, Takunori Taira of Japan’s National Institutes of Natural Sciences.

According to Taira, conventional spark plugs pose a barrier to improving fuel economy and reducing emissions of nitrogen oxides (NOx), a key component of smog.

Spark plugs work by sending small, high-voltage electrical sparks across a gap between two metal electrodes. The spark ignites the air-fuel mixture in the engine’s cylinder—producing a controlled explosion that forces the piston down to the bottom of the cylinder, generating the horsepower needed to move the vehicle.

Engines make NOx as a byproduct of combustion. If engines ran leaner – burnt more air and less fuel – they would produce significantly smaller NOx emissions.

Spark plugs can ignite leaner fuel mixtures, but only by increasing spark energy. Unfortunately, these high voltages erode spark plug electrodes so fast, the solution is not economical. By contrast, lasers, which ignite the air-fuel mixture with concentrated optical energy, have no electrodes and are not affected.

Lasers also improve efficiency. Conventional spark plugs sit on top of the cylinder and only ignite the air-fuel mixture close to them. The relatively cold metal of nearby electrodes and cylinder walls absorbs heat from the explosion, quenching the flame front just as it starts to expand.

Lasers, Taira explains, can focus their beams directly into the center of the mixture. Without quenching, the flame front expands more symmetrically and up to three times faster than those produced by spark plugs.

Equally important, he says, lasers inject their energy within nanoseconds, compared with milliseconds for spark plugs. “Timing – quick combustion – is very important. The more precise the timing, the more efficient the combustion and the better the fuel economy,” he says.

Lasers promise less pollution and greater fuel efficiency, but making small, powerful lasers has, until now, proven hard. To ignite combustion, a laser must focus light to approximately 100 gigawatts per square centimeter with short pulses of more than 10 millijoules each.

“In the past, lasers that could meet those requirements were limited to basic research because they were big, inefficient, and unstable,” Taira says. Nor could they be located away from the engine, because their powerful beams would destroy any optical fibers that delivered light to the cylinders.

Taira’s research team overcame this problem by making composite lasers from ceramic powders. The team heats the powders to fuse them into optically transparent solids and embeds metal ions in them to tune their properties.

Ceramics are easier to tune optically than conventional crystals. They are also much stronger, more durable, and thermally conductive, so they can dissipate the heat from an engine without breaking down.

Taira’s team built its laser from two yttrium-aluminum-gallium (YAG) segments, one doped with neodymium, the other with chromium. They bonded the two sections together to form a powerful laser only 9 millimeters in diameter and 11 millimeters long (a bit less than half an inch).

The composite generates two laser beams that can ignite fuel in two separate locations at the same time. This would produce a flame wall that grows faster and more uniformly than one lit by a single laser.

The laser is not strong enough to light the leanest fuel mixtures with a single pulse. By using several 800-picosecond-long pulses, however, they can inject enough energy to ignite the mixture completely.

A commercial automotive engine will require 60 Hz (or pulse trains per second), Taira says. He has already tested the new dual-beam laser at 100 Hz. The team is also at work on a three-beam laser that will enable even faster and more uniform combustion.

The laser-ignition system, although highly promising, is not yet being installed into actual automobiles made in a factory. Taira’s team is, however, working with a large spark-plug company and with DENSO Corporation, a member of the Toyota Group.
Altitude is offline   Reply With Quote
Old 04-24-2011, 08:02 PM   #2
why?
Only Happy When it Rains
 
why?'s Avatar
 
Drives: Yaris LB
Join Date: Jan 2006
Location: harnett county NC
Posts: 4,132
sounds like that would be better for everyone. I just wonder how long it would take and if they could be used on older cars.
__________________
Colin Chapman disciple
why? is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
article on spark plugs and the fit kngrsll Performance Modifications 4 08-01-2009 11:50 PM
did autolite spark plugs screw up coil or coils ?? la_scanner DIY / Maintenance / Service 20 04-09-2009 02:07 PM
Upgraded Spark Plugs For Boost whooppee777 Forced Induction Forum 9 02-14-2009 01:53 PM
INTEREST: Bumper Plugs (Blazing Blue Metallic) R0ME0 Items for Sale by private party 19 03-13-2007 09:22 AM
Extra parts? (Or where do these plugs go) jah General Yaris / Vitz Discussion 6 05-01-2006 10:33 PM


All times are GMT -4. The time now is 05:14 AM.




YarisWorld
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.