Who needs spark plugs?


#1

Check out this news item. What do you tink?

OKAZAKI, Japan – Automakers are now one step closer to replacing spark
plugs for internal combustion engines with laser igniters for cleaner, more
efficient and more economical vehicles.
Lasers have been discussed as a promising alternative ignition source for
efficient internal combustion engines because they promise less pollution and
greater fuel efficiency. Until recently, it was difficult to make small, powerful
lasers that could focus light to ~100 GW/cm² with short pulses of more than
10 mJ each, needed to ignite combustion.
Scientists from Japan’s National Institutes of Natural Sciences overcame
this problem by making composite lasers from ceramic powders. They heated
the powders to fuse them into optically transparent solids, and embedded
metal ions in them to tune their properties. Ceramics are easier to tune optically
than conventional crystals and are much stronger, more durable and
thermally conductive, enabling them to dissipate the heat from an engine
without breaking down.
The research team built its laser from two yttrium aluminum gallium
segments, one doped with neodymium, the other with chromium. The two
segments were bonded together to form a powerful laser only 9 mm in diameter
and 11 mm long. The composite generated two laser beams that could
ignite fuel in two separate locations simultaneously, producing a flame wall
that grows faster and more uniformly than one lit by a single laser.
Not strong enough to light the leanest fuel mixtures with a single pulse,
the laser can, however, inject enough energy to ignite the mixture completely
by using several 800-ps-long pulses. It was tested at 100 Hz – a commercial
automotive engine will require only 60 Hz.
Although promising, the system is not yet being installed into automobiles.
The team is working on a three-beam laser that will enable even faster and
more uniform combustion. Supported by the Japan Science and Technical
Agency, the work was presented at CLEO 2011.


#2

Interesting but nothing like replacing a $7 spark plug with a $300 igniter.


#3

Er, um, are spark plugs really that terrible?


#4

Maybe this is how we are going to get to the 50+ MPG CAFE standards. You pay an extra $10,000 upfront and then less on gas. I think I should go stock up on some “old school” cars with spark plugs.


#5

It sounds great, but in sadness it will probably take a regular guy one step farther away from maintaining his own car.


#6

This is a technology I would definitely avoid for the first model year it’s used. I have little doubt if it makes it to production that it will be as flaky and troublesome as early fuel injection was.


#7

galant 12:29AM “Maybe this is how we are going to get to the 50+ MPG CAFE standards”

For some reason, I don’t believe that it’s the deficiencies of old school ion-plasma ignition that’s keeping cars from getting 50 mpg.


#8

Don’t be so negative. After all, laser technology is found in the cheapest of CD players. Spark plugs are one time shots where the laser appears to give the computer better control. Better grilled hamburgers are just around the corner too. Dad does the kid’s while in the bun from thirty feet away. What’s not to like?


#9

What is the source of the article?


#10

Looks like the same thing we talked about in April:
http://community.cartalk.com/discussion/2271815/laser-spark-plugs/p1


#11

It sounds like the laser would be designed to solve the problem of incomplete ignition of the fuel mixture. Wouldn’t a two-plug-per-cylinder design also address that problem?


#12

Different isn’t neccessarily better…just different.
Alternate choice…
plan B


#13

Wouldn’t a two-plug-per-cylinder design also address that problem?

My wifes Datsun 510 had that setup with the Naps-Z engine.


#14

Whitey, It’s from the July issue of Photonics Spectra.

Dagosa is correct, though I detect a little sarcasm: CD and DVD players use lasers to read and write data. Laser pointers are quite inexpensive, too. Large scale manufacturig and use would drive the cost down. Laser weapons aren’t the cost model here.

I don’t think tht this couuld be a retrofit. To me, laser igniters have to be fitted when the engine is built. I would expect that if laser igniters make it to production, they will show up in very expensive cars first and then migrate to cars that we are more likely to drive. After all, if something goes wrong on a very expensive car, how many customers can you alienate? I would also expect that someone like Toyota would be an early adopter since they have a large research budget.

I suppose that this might be one way to help meet new CAFE standards, but it might also add power when gas is burned more efficiently. The users (auto companies) have to decide how it bests fits into their plans to lure customers.


#15

Given that they haven’t been tried in an engine yet, I imagine they’re 10 years away, or more.


#16

Yeah, 10 years, easy. But it’s still a fun article.


#17

Yes, I bet they’ll have advantages we really can’t think of. They won’t be a replacement for spark plugs, just to ignite the gas as a point in the chamber. They could be aimed, focused, and adjusted to create various geometries and time periods for ignition. Combine that with the ability of direct injection to put gas into the cylinder on a very specific shedule, in a very specific area, and I imagine lots of options are created for improving fuel efficiency.

But you still can’t cheat mother nature…


#18

Texases, you’ve been reading my mind again. Rather than think about this as simply a direct replacement for sparkplugs in a multiport engine, we need to think of this in combination with direct injection systems and with the fluid dynamics of the cylinder. It’s possible that some more mileage can be squeezed out of the engines without reliability tradeoffs. Perhaps even more of the combusion process can be incited at the top of the power stroke where more of it can be converted to power. Perhaps redesign of the cylinders will be a part of this.

But Galant made a good point too. This might help meet new standards, but how much cost will it add to the car?


#19

How much will it cost? Or how long will it take for the cost savings to offset the added costs?

Suppose one drives 12K/year, gets 20 mpg, and gas costs $4.00/gallon. If the igniters can raise the mileage to 22 mpg, that saves $240.00/year.


#20

Joe, it won’t matter if the price of the car is too high to purchase.