Skip to Content
Find More Like This
Return to Search

Laser Spark Distribution and Ignition System

A method of creating sparks in lean fuel/air mixtures without expensive,short-lifetime spark plugs

National Energy Technology Laboratory

Contact NETL About This Technology

Technology Marketing Summary
Disclosed in this patent is NETL’s laser spark distribution and ignition system, which reduces the high-power optical requirements
normally needed for such a system by using optical fibers to deliver low-peak-energy pumping pulses to a laser amplifier or laser
oscillator. Laser spark generators then produce a high-peak-power laser spark from a single low power pulse. The system has applications in natural gas fueled reciprocating engines, turbine combustors, explosives, and laser induced breakdown spectroscopy diagnostic sensors.
Description
Current emission regulations relating to NOx require reciprocating engines
to operate at very lean fuel/air mixtures. The excess air keeps the combust-
ing gases cooler and limits thermal NOx development. At the same time,
the lean mixture requires much more energy to be delivered to the spark
plug for successful ignition, which leads to rapid erosion of spark plug
electrodes and short spark plug lifetimes (only hundreds of hours). The
resulting maintenance costs are thus very high, especially for natural gas
fueled energy generation engines which must run continuously for
thousands of hours.

Many researchers have explored the possibility of substituting a fiber
optics system capable of transmitting a laser-induced plasma spark to
an ignition chamber, thereby eliminating the need for spark plugs. But
the high energies needed to produce a plasma spark usually destroy
the optical fiber. A fiber of sufficient diameter to handle the energy and
resist destruction produces a laser spot so diffuse that is incapable of
generating a spark.
NETL scientists and engineers have met this challenge by combining a
low power optical pumping source, an optical distributor, and a number
of distinct spark generators. The optical pumping source, having a peak
optical power less than 1,000 Watts so as not to destroy the optical fibers,
is coupled to the optical distributor. The distributor is connected to a
number of spark generators, which can produce a high energy spark from
the original low power laser pulse. The laser spark generators can be
either laser amplifiers or laser oscillators. The sparking sequence is
directed by the optical distributor.
Benefits
A method of creating sparks in lean fuel/air mixtures without expensive,short-lifetime spark plugs

A means of meeting low NOx emissions requirements in enginers and combustors

A novel, optical-based method of operating natural gas fueled reciprocating engines, turbine combustors, explosives,

and laser induced breakdown spectro-scopy diagnostic sensors
Applications and Industries

Natural gas fueled reciprocating engines, turbine combustors, explosives, and laser induced breakdown spectroscopy diagnostic sensors

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 7,421,166
Patent
7,421,166
Laser spark distribution and ignition system
A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.
09/02/2008
Issued
Technology Status
Development StageAvailabilityPublishedLast Updated
PrototypeAvailable03/12/201302/23/2016

Contact NETL About This Technology

To: Jessica Sosenko <Jessica.Sosenko@netl.doe.gov> <techtransfer@netl.doe.gov>