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.
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?
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.
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.
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?