laserignitionsystem IS A SEMINAR DONE BY STUDENTS AT SNM PTC MALIANAKARA

laserignitionsystem IS A SEMINAR DONE BY STUDENTS AT SNM PTC MALIANAKARA

1. Seminar Presentation on
LASER IGNITION SYSTEM
B Y
AUTHORISED STAFF ADARSH SB
JACOB ABRAHAM S5 MECHANICAL
ROLL NO : 7

2. INTRODUCTION
•It’s widely accepted that the internal combustion engines will
continue to power our vehicles. Hence , as the global
mobilization of peoples and goods increases , advances in
combustion and after-treatment are needed to reduce the
environmental impact of the continued use of IC engine
vehicles.
•New engines are becoming increasingly complex, with
advanced combustion mechanism that burn an increasing
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, a LIS
should be a favourable ignition source in terms of lean burn
characteristics and system flexibility. So , in this seminar we’ll
be discussing the implementation and impact of LIS on IC
engines.

3. What is LASER ?
A laser is a device that emits electromagnetic radiation
through a process of optical amplification based on the
stimulated emission of photons. The term “laser” is an
acronym for Light Amplification by Stimulated Emission
of Radiation. Lasers provide intense and unidirectional
beam of light. Laser light is mono chromatic (one
specific wavelength).

4. How does laser work?
Laser are mono chromatic (one specific wavelength). It starts
with the electrons. By sending energy to a system we can
achieve what is known as population inversion. This means
that there are more electrons in the excited states than those
in the lower energy states. As one electron releases energy (a
photon), the other electrons strangely seem to communicate
with each other and also begin releasing photons.

5. Types of lasers
There are four types of lasers they are as following:
1• Chemical laser :Lasers that obtain their energy through
chemical reaction.hydrogen fluoride laser (2700-2900nm)
2• Exclimer laser : It produce ultraviolet light
3• Solid-state laser : neodymium-doped yttrium aluminium
garnet (YAG) Nd:YAG Lasers can 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/DVD players.

6. Background Study of Ignition in IC Engine
What is ignition ?
Ignition is the process of starting radical reactions until a self-
sustaining flame has developed. One can distinguish between
auto ignition, induced ignition and photo –ignition , the latter
being caused by photolytic generation of radicals.
Ignition Types
A. Compression Ignition (CI) or Auto Ignition : At certain values
of temperature and pressure a mixture will ignite
spontaneously
B. Induced Ignition : A process where a mixture, which would
not ignite by it, is ignited locally by an ignition source

7. Conventional Sparking Plug Ignition
Conventional spark plug ignition has been used for many
years. For ignition of a fuel-air mixture the fuel-air mixture
is compressed and at the right moment a high voltage is
applied to the electrodes of the spark plug.

8. Current spark ignition system

9. WHAT’S THE PROBLEM ?
•The following are the drawbacks of SI:
1. Location of spark plug is not flexible as it requires shielding
of plug from immense heat and fuel spray
2. It require frequent maintenance to remove carbon deposit.
3. Leaner mixtures cannot be burned efficiently.
4. Degradation of electrodes at high pressure and
temperature.
5. Flame propagation is slow.
6. Multi point fuel ignition is not feasible.
7. Higher turbulence levels are required
8. It is not possible to ignite inside the fuel spray
To overcome the above mentioned disadvantages LIS is being
sought after

10. WHY LASER IGNITION?
•Regulation on NOx emissions are pushing us toward leaner air/fuel
ratios (higher ratio of air to fuel).
-These leaner air/fuel ratios are harder to ignite and require higher
ignition energies. Spark plugs can ignite leaner fuel mixtures, but
only by increasing spark energy. Unfortunately, these high voltage
erode spark electrodes so fast, 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 gas is more difficult to ignite than gasoline due to the strong
carbon to hydrogen bond energy.
-Lasers are monochromatic, so it will be much easier to ignite
natural gases and direct the laser beam to an optimal ignition
location.
•Because of the requirement for an increase in ignition energy, spark
plug life will decrease for natural gas engines.
-Laser spark plug ignition system will require less power than
traditional spark plugs. therefore outlasting spark plugs.

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.
-Laser can be focused and split into multiple
ignition points, which means it can give a far better chance of
ignition.
•laser promise less pollution and greater fuel efficiency, but making
small, powerful lasers has, until now, proven hard. To ignite
combustion , a laser must focus light to approximately 100 GW
/cm^2 with short pulses of more than 10 mJ each.
•The laser also produces more stable combustion so you need to put
less fuel into the cylinder, so increase the efficiency.
•Optical wire and laser set up is much smaller than the current spark
plug model, allowing different design opportunities.
•Lasers can reflect back from inside the cylinders relaying
information such as fuel type and level of ignition creating optimum
performance.
•laser use will reduce erosion.

12. TYPES OF LASER IGNITION
Basically, energetic interactions of a laser with a gas may be classified into
one of the following four schemes as described in
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 ignition method,
because typically the light photon energy is invisible or UV range of
spectrum, multiphoton processes are required for molecular ionization.
3. Resonant breakdown :The resonant breakdown laser ignition process
involves, first, a non resonant multiphoton dissociation of molecules
resulting to freed atoms, followed by a resonant photo ionization of these
atoms.
4.Photochemical mechanisms :In photochemical ignition approach, very
little direct 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 :Laser ignition encompasses the
nanosecond domain of the laser pulse itself to the duration of the entire
combustion lasting several hundreds of milliseconds

13. NON RESONANT BREAKDOWN
•In NRB, the focused laser beam creates an electric field of sufficient intensity to
cause dielectric breakdown of the air fuel mixture.
•The process begins with multi-photon ionisation of few gas molecules which
releases electrons that readily absorb more photons via the inverse
bremsstrahlung process to increase their kinetic energy.
•Electrons liberated by this means collide with other molecules and ionise them,
leading to an electron avalanche, and breakdown of the gas
•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.
•Thus this avalanche of electrons and resultant ions collide with other producing
immense heat hence creating plasma which is sufficiently strong to ignite the fuel.

14. LASER IGNITION SYTEM FOR AN INTERNAL
COMBUSTION ENGINE
•Laser ignition will replace the spark plug seen in current
gasoline engines

15. COMPONENTS OF LASER IGNITION ENGINE
•Power Source
•Combustion Chamber Windows
•Optic Fibre Wire
•Focusing Unit
•Laser Spark Plug

16. HOW LASER IGNITION WORKS?
•The laser ignition system has a laser transmitter with a fibre-optic cable
powered by the car’s battery.
•It shoots the laser beam to a focusing lens that would consume a much
smaller space than current spark plugs.
•The lenses focus the beams into 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
The laser beam passed through a convex 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. The focal point is adjusted where
the ignition is required to have.
the plasma generated by the Laser beam
results in two of the following actions:
1.Emission of high energy photons
2.Generation of shock waves
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.
The shock waves carry energy out wards from
the laser beam and thus help in propagation of
flame as shown in the above figure.

18. IGNITION IN COMUSTION CHAMBER
CONSTRUCTION

19. ENGINE EXPERIMENTS
•LASER USED IS ND:YAG (neodymium-doped yttrium aluminium
garnet)

20. ADVANTAGES OF LIS
• More intense spark
• Free choice of the ignition location within the combustion chamber
• Leaner fuel can burn effectively
• Laser ignition system could cope with a stratified charge.
• Flame propagation is relatively fast resulting in shorter combustion time
• Easier possibility of multipoint ignition
• NOx emission
Engines would produce less NOx if they burnt more air and less fuel,
but they would require the plugs to produce higher energy sparks in
order to do so. Less NOx emission
• Absence of quenching effects by the spark plug electrodes
• No erosion effects as in the case of the spark plugs => lifetime of a laser
ignition
• System expected to be significantly longer than that of a spark plug
• High load/ignition pressures possible => increase in efficiency
• Precise ignition timing possible
• Easier possibility of multipoint ignition

21. DISADVANTAGES
•High system cost
•Concept proven, but no commercial system available in
market yet.
•Laser induced optical damage

22. APPLICATON
•According to the latest international reports, Mazda’s
upcoming rotary sports car could feature laser ignition
technology. This would replace the spark plug ignition system
which is currently applied to every petrol car on the market.
It’s also a setup a revolution in spark plug which has been not
change around since 1860
•Ford motor

23. CONCLUSION
Laser ignition system allows almost free choice of the ignition
location within the combustion chamber, even inside the fuel
spray. Significant reductions in fuel consumption as well as
reductions of exhaust gases show the potential of the laser
ignition process. Minimum ignition energy is mainly
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 different laser wavelengths.
Although the laser will need to fire more than 50 times per
second to produce 3000 RPM, it will require less power than
current spark plug. The lasers can also reflected back from
inside the cylinders to relay information based on fuel type
used and the level of ignition, enabling cars to readjust the
quantities of air and fuel for optimum performance.

24. References
•[1] Bergmann and Schaefer, Lehrbuch der Experimental physik:
Elektrizit¨at und Magnetismus, vol. 2, Walter de Gruyter Berlin,
1981.
•[2] J. Ma, D. Alexander, and D. Poulain, “Laser spark ignition and
combustion characteristics of methane-air mixtures,” Combustion
and Flame, pp. 492–506, 1998
•[3] J. Syage, E. Fournier, R. Rianda, and R. Cohn, “Dynamics of flame
propagation using laser-induced spark initiation: Ignition energy
measurements,” Journal of Applied Physics, pp. 1499–1507, 1988.
[4] Lambda Physik, Manual for the LPX205 Excimer Laser, 1991
•[5] M. Gower, “Krf laser-induced breakdown of gases,” Opt.
Commune, pp.43–45, 1981.
•[6] R. Hill, “Ignition-delay times in laser initiated combustion,”
Applied Optics, pp. 2A239–2242, 1981.
•[7] T. Huges, plasma and laser light,Adam Hilger,Bristol,1975.

25. THANK YOU