http://www.autoblog.com/2011/06/28/mazda-rumored-to-use-laser-ignition-for-next-gen-rotary/

http://m.motortrend.com/wot/we-hear-next-mazda-rotary-engine-to-employ-laser-ignition-91085.html


-Dan Gorsline.


Wankel Rotary Power


This is 2011 if it worked it would be here by now.
A laser with enough power is not inexpensive.

Paul Lamar

No doubt that lasers can be used to spark and the benefits of a
distributed ignition within the chamber are obvious

Lasers are now made "dirt" cheap and are highly reliable (20 years
continuous use). A small 2" wafer can be diced into 10,000 semiconductor
lasers the size of a grain of salt. There is a 99.999% chance that this
email arrived to everyone after passing several lasers and several EDFA
(Optical Amplifiers driven by another laser) over fiber optics

The technical challenge is the keeping the lens into the chamber clean
enough over time to keep working. Lasers need a translucent window /
lens made from quartz or sapphire. These are also readily available and
relatively cheap. The challenge is keeping the quartz window clean and
free from soot build up over time. As soot and other combustion deposits
builds up on the window/lens, it becomes opaque and unable to pass the
laser light

Several companies are working on this including a division of DENSO
(second largest global auto industry supplier) but it will be a long
time, if ever, before we see it in production
(PS I spent 16 years in the laser industry)
Regards
Simon Saba

What are the typical powers of a laser the size of a grain of salt?
Are there any fast laser optical isolators available?
Fast in the region of nanoseconds. Maybe the problem is not
the laser but the optical transistor or detector come to think of it.

Paul Lamar

Depending on the wavelength, these lasers can go to 10 Watts at the 920
nanometer range
for lasers anything in the Watt region is very high power (enough for
metalworking). In general, lower wavelength lasers, the photons have
more energy

I am not sure what wavelength rage is best to achieve spark ignition. I
remember reading a lot a paper about using the 1550 nanometer region to
leverage the huge volume of telecommunications lasers. The attached data
sheet shows the laser are roughly 1" x 0.5"  0.5" form factor but 90% of
that volume is the heat sink. This is a fiber coupled laser meaning the
laser can be 1 to several meters away from the engine.

In general lasers can be modulated at very high frequency. When I left
the industry a few years ago 10GHz modulation was considered "old
technology" and the next frontier was 25 GHz and 40 GHz

There is a US company called princeton optronics doing some work in this
area https://www.sbir.gov/sbirsearch/detail/689475

There are others years ahead of Princeton Optronics researching this,
but nothing came close to commercialization

Regards
Simon Saba

Thanks for the info Simon.


Paul Lamar

Simon Saba

What is the typical efficiency for a 10W output laser?


Robert LeClercq



Lasers are getting a lot more efficient these days... approximately 40% for these high power laser diodes

Regards

Simon Saba



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