Seminar Presentation

1. A
SeminarPresentation
on
LASERIGNITIONSYSTEM IN IC
ENGINE
GUIDED BY,
DR. S. I. KOLHE
SUBMITED BY,
Shubham .S.Badhe

2. INTRODUCTION
• It’s widely accepted that the internal combustion engineswill
continue to power our vehicles. Hence, asthe global
mobilization of peoples and goods increases , advancesin
combustion and after-treatment are needed to reduce the
environmental impact of the continued useof ICengine
vehicles.
• New engines are becoming increasingly complex, with
advanced combustion mechanism that burn anincreasing
variety of fuels to meet future goals on performance, fuel
economy and emissions.
• One of the alternative is the laser ignition system (LIS)being
described here. compared to a conventional sparkplug, aLIS
should be afavourable ignition source in terms oflean burn
characteristics and systemflexibility. So, in this seminar we’ll
be discussing the implementation and impact of LISonIC
engines.

3. What is LASER?
Alaser is a device that emits electromagnetic radiation
through aprocessof optical amplification basedonthe
stimulated emission of photons. Theterm “laser” is an
acronym for LightAmplification by StimulatedEmission
of Radiation. Lasersprovide intense and unidirectional
beam of light. Laserlight is mono chromatic (one
specific wavelength).

4. How does laserwork?
Laserare mono chromatic (one specific wavelength). It starts
with the electrons. Bysending energy to asystem we can
achieve what is known aspopulation inversion. Thismeans
that there are more electrons in the excited states than those
in the lower energy states. Asone electron releases energy(a
photon), the other electrons strangely seemto communicate
with each other and also begin releasingphotons.

5. Types of lasers
There are four types of lasers they areasfollowing:
1• Chemical laser :Lasersthat obtain their energy through
chemical reaction. hydrogen fluoride laser(2700-2900nm)
2• Exclimerlaser : It produce ultraviolet light
3• Solid-state laser : neodymium-doped yttrium aluminium
garnet (YAG)Nd:YAGLaserscan produce high powers in the
infrared spectrum at 1064
4•Semiconductor laser : laser diodes produce wavelengths from
405 nm to 1550 nm. Low power laser diodes are used in laser
pointers, laser printers, and CD/DVDplayers.

6. Background Study of Ignition in ICEngine
What is ignition?
Ignition is the process of starting radical reactions until aself-
sustaining flame hasdeveloped. Onecandistinguish between
auto ignition, induced ignition and photo – ignition , the latter
being causedby photolytic generation of radicals.
Ignition Types
A.Compression Ignition (CI) orAuto Ignition : At certain values
of temperature and pressure amixture will ignite
spontaneously
B. Induced Ignition : Aprocess where amixture, whichwould
not ignite by it, is ignited locally by an ignition source

7. Conventional Sparking PlugIgnition
Conventional spark plug ignition hasbeen used for many
years. For ignition of afuel-air mixture the fuel-airmixture
is compressed and at the right moment ahigh voltage is
applied to the electrodes of the spark plug.

8. Current spark ignitionsystem

9. WHAT’S THEPROBLEM ?
• Thefollowing are the drawbacks ofSI:
1. Location of spark plug is not flexible asitrequires shielding
of plug from immense heat and fuelspray
2.Itrequire frequent maintenance to remove carbon deposit.
3. Leaner mixtures cannot be burned efficiently.
4. Degradation of electrodes at high pressureand
temperature.
5. Flame propagation is slow.
6.Multi point fuel ignition is not feasible.
7. Higher turbulence levels arerequired
8.It is not possible to ignite inside the fuel spray
Toovercome the above mentioned disadvantages LISis being
sought after

10. WHY LASERIGNITION?
• Regulation on NOxemissions are pushing ustoward leaner air/fuel
ratios (higher ratio of air to fuel).
- Theseleaner air/fuel ratios are harder toignite and require higher
ignition energies. Sparkplugs canignite leaner fuel mixtures, but
only by increasing spark energy. Unfortunately, these high voltage
erode spark electrodes sofast, the solution is not economical. By
contrast, lasers, which ignite the air-fuel mixtures with
concentrated optical energy, have no electrodes and are not
affected.
• Natural gasis more difficult to ignite than gasoline due to the strong
carbon to hydrogen bondenergy.
- Lasers are monochromatic, so it will be much easier to ignite
natural gases and direct the laser beam to an optimal ignition
location.
• Becauseof the requirement for an increase in ignitionenergy, spark
plug life will decreasefor naturalgasengines.
- Laserspark plug ignition system will require lesspowerthan
traditional spark plugs. therefore outlasting sparkplugs.

11. WHY LASER IGNITION? ...continued
• Ignition sites for spark plugs are at a fixed location at the top of the
combustion chamber that only allows for ignition of the air/fuel
mixtures closest to them.
-Lasercanbe focused and split into multiple
ignition points, which means it cangive afar betterchanceof
ignition.
• laser promise lesspollution and greater fuel efficiency, butmaking
small, powerful lasers has, until now, proven hard. Toignite
combustion , alaser must focus light to approximately 100GW
/cm^2 with short pulsesof more than 10mJeach.
• Thelaser also produces more stable combustion soyou need to put
lessfuel into the cylinder, soincrease the efficiency.
• Optical wire and laser set up is much smaller than the currentspark
plug model, allowing different designopportunities.
• Laserscanreflect back from inside the cylinders relaying
information suchasfuel type and level of ignition creatingoptimum
performance.
• laser usewill reduceerosion.

12. TYPESOFLASER IGNITION
Basically, energetic interactions of alaser with agasmay be classified into
one of the following four schemesasdescribedin
1.Thermal initiation :In thermal initiation of ignition, there is no electrical
breakdown of the gas and a laser beam is used to raise the kinetic energy
of target molecules in translational, rotational, or vibrational forms.
2.Non-resonant breakdown :In non resonant breakdown ignitionmethod,
becausetypically the light photon energy is invisible or UVrange of
spectrum, multiphoton processesare required for molecularionization.
3.Resonant breakdown :Theresonant breakdown laser ignition process
involves, first, anon resonant multiphoton dissociation of molecules
resulting to freed atoms, followed by aresonant photo ionization of these
atoms.
4.Photochemical mechanisms :In photochemical ignition approach, very
littledirect heating takes place and the laser beam brings about molecular
dissociation leading to formation of radicals (i.e., highly reactive chemical
species).
5.Laser Ignition process along time :Laserignition encompassesthe
nanoseconddomain of the laser pulse itself to the duration of the entire
combustion lasting severalhundreds of milliseconds

13. NON RESONANTBREAKDOWN
• In NRB,the focused laser beam creates an electric field of sufficient intensityto
cause dielectric breakdown of the air fuelmixture.
• Theprocess begins with multi-photon ionisation of few gasmolecules which
releases electrons that readily absorb more photons via the inverse
bremsstrahlung process to increase their kineticenergy.
• Electrons liberated by this means collide with other molecules and ionisethem,
leading to an electron avalanche, and breakdown of thegas
• Multi-photon absorption processes are usually essential for the initial stage
of breakdown because the available photon energy at visible and near IR
wavelengths is much smaller than the ionisation energy.
• For every short pulse duration (few picoseconds) the multi photon processes
alone must provide breakdown , since there is insufficient time for electron-
molecule collision to occur.
• Thusthis avalanche of electrons and resultant ions collide with otherproducing
immense heat hence creating plasma which is sufficiently strong to ignite thefuel.

14. LASER IGNITION SYTEM FOR ANINTERNAL
COMBUSTION ENGINE
• Laserignition will replace the spark plug seenincurrent
gasoline engines

15. COMPONENTS OFLASER IGNITION ENGINE
• Power Source
• Combustion ChamberWindows
• Optic FibreWire
• FocusingUnit
• LaserSpark Plug

16. HOW LASER IGNITIONWORKS?
• Thelaser ignition system hasalaser transmitter with afibre-optic cable
powered by the car’sbattery.
• It shoots the laser beam to afocusing lens that wouldconsume amuch
smaller spacethan current sparkplugs.
• Thelenses focus the beamsinto an intense pinpoint of light by passing
through an optical window , and when the fuel is injected into the engine ,
the laser is fired and produces enough energy (heat) to ignite the fuel.

17. HOW LASER IGNITION WORKS?...continued
Thelaser beam passed through aconvex lens
diverge the beam and make it immensely
strong and sufficient enough to start
combustion at that point. Hence the fuel is
ignited, at the focal point, with the mechanism
shown above. Thefocal point is adjusted where
the ignition is required tohave.
the plasma generated by the Laserbeam
results in two of the following actions:
1.Emission of high energyphotons
2.Generation of shockwaves
The high energy photons, heat and ionise the
charge present in the path of laser beam which
can be seen from the propagation of the flame
which propagates longitudinally along the laser
beam.
Theshock wavescarry energy out wards from
the laser beam and thus help in propagation of
flame asshown in the abovefigure.

18. IGNITION IN COMUSTIONCHAMBER
CONSTRUCTION

19. ENGINE EXPERIMENTS
• LASERUSEDISND:YAG(neodymium-doped yttrium aluminium
garnet)

20. ADVANTAGES OFLIS
• More intensespark
• Free choice of the ignition location within the combustion chamber
• Leaner fuel canburn effectively
• Laserignition system could cope with astratified charge.
• Flamepropagation is relatively fast resulting in shorter combustiontime
• Easierpossibility of multipoint ignition
• NOxemission
Engineswould produce lessNOxif they burnt more air and lessfuel,
but they would require the plugs to produce higher energy sparksin
order to do so. LessNOxemission
• Absenceof quenching effects by the spark plugelectrodes
• No erosion effects asin the caseof the spark plugs =>lifetime of alaser
ignition
• Systemexpected to be significantly longer than that ofaspark plug
• High load/ignition pressures possible =>increase in efficiency
• Preciseignition timing possible
• Easierpossibility of multipoint ignition

21. DISADVANTAGES
• High system cost
• Concept proven, but no commercial system availablein
market yet.
• Laserinduced optical damage

22. APPLICATON
• According to the latest international reports, Mazda’s
upcoming rotary sports car could feature laser ignition
technology. Thiswould replace the spark plug ignitionsystem
which is currently applied to every petrol car on the market.
It’s also asetup arevolution in spark plug which hasbeennot
change around since1860
• Ford motor

23. CONCLUSION
Laserignition system allows almost free choice of the ignition
location within the combustion chamber, even inside thefuel
spray.Significant reductions in fuel consumption aswell as
reductions of exhaust gasesshow the potential of the laser
ignition process. Minimum ignition energy ismainly
determined by the necessary “self-cleaning” mechanism at
the beam entrance window from combustion deposits and
not by engine related parameters. No differences of the laser
ignition process could be found at differentlaser wavelengths.
Although the laser will need to fire more than 50 times per
second to produce 3000 RPM,itwill require lesspower than
current spark plug. Thelasers canalso reflected back from
inside the cylinders to relay information based on fuel type
used and the level of ignition, enabling carsto readjust the
quantities of air and fuel for optimum performance.

24. THANK YOU