Internal combustion engines play a dominant role in transportation and energy production. In technical appliances such as internal combustion engines, reliable ignition is necessary for adequate system performance. Unfortunately, conventional spark plug ignition shows a major disadvantage with modern spray-guided combustion processes since the ignition location cannot be chosen optimally. A laser ignition source has the potential of improving engine combustion with respect to conventional spark plugs.

1. Laser Ignition for
Internal Combustion Engines
VS
Submitted by:-
Nand Kumar Sharma
16ERAME031
B.TECH.4TH
YEAR
MECHANICAL ENGG.
Submitted to:-
Mr. Gourav purohit
Head of Department
Mechanical Department

2. CONTENTS
⚫ INTRODUCTION
⚫ CONVENTIONAL SPARKING PLUG IGNITION
⚫ DRAWBACKS OF CONVENTIONAL IGNITION SYSTEM
⚫ WHAT IS A LASER?
⚫ LASER Ignition
⚫ Types of Laser Ignition
⚫ SETUP OF LASER IGNITION
⚫ Working principle
⚫ FLAME PROPAGATION IN COMBUSTION CHAMBER
⚫ Why Laser Ignition?
⚫ Comparative Advantages of Laser Ignition
⚫ Additional advantages of Laser Ignition
⚫ COMPERISION S.P AND L.I
⚫ Future Research Needs and Shortcomings
⚫ Summary
⚫ Conclusion
⚫ REFERENCES

3. INTRODUCTION
⚫ Internal combustion engines play a dominant role in transportation and
energy production.
⚫ In technical appliances such as internal combustion engines, reliable
ignition is necessary for adequate system performance.
⚫ Unfortunately, conventional spark plug ignition shows a major disadvantage
with modern spray-guided combustion processes since the ignition location
cannot be chosen optimally.
⚫ A laser ignition source has the potential of improving engine combustion
with respect to conventional spark plugs.

4. 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.

5. Standard Spark Plug Ignition in an
Internal Combustion Engine
⚫ Current internal combustion gasoline engines use spark plugs to ignite the
air/fuel mixture in each cylinder (located at the top of the combustion
chamber).

6. DRAWBACKS OF CONVENTIONAL IGNITION
SYSTEM
⚫ Location of spark plug is not flexible as it requires shielding of plug from
immense heat and fuel spray.
⚫ Leaner mixtures cannot be burned, ratio between fuel and air has to be
within the correct range.
⚫ Flame propagation is slow.
⚫ Erosion of spark plug electrodes.
⚫ Degradation of electrodes at high pressure and temperature.

7. WHAT IS A 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

8. LASER Ignition
⚫ Laser ignition, or laser-induced ignition, is the process of starting combustion by the
stimulus of a laser light source.
⚫ Laser ignition uses an optical breakdown of gas molecules caused by an intense
laser pulse to ignite gas mixtures.
⚫ The beam of a powerful short pulse laser is focused by a lens into a combustion
chamber and near the focal spot and hot and bright plasma is generated, see fig.

9. 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
2. Non-resonant breakdown
3. Resonant breakdown
4. Photochemical mechanisms

10. Laser Ignition System for an
Internal Combustion Engine
Laser ignition will replace the spark plug seen in current gasoline
engines.

11. SETUP OF LASER IGNITION

12. Working principle
⚫ The laser ignition system has a laser transmitter with a fiber-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, and when the fuel is injected into the engine, the laser is
fired and produces enough energy (heat) to ignite the fuel.
⚫ Below is a diagram of the laser arrangement:

13. FLAME PROPAGATION IN COMBUSTION
CHAMBER

14. Why Laser Ignition?
⚫ Regulations 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 voltages
erode spark plug electrodes so fast, the solution is not economical.
By contrast, lasers, which ignite the air-fuel mixture 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.
⚫ 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 mixture
closest to them.
⚫ Lasers can be focused and split into multiple beams to give multiple
ignition points, which means it can give a far better chance of ignition.

15. Why Laser Ignition? (continued)
⚫ Lasers 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 gigawatts per square centimeter with short
pulses of more than 10 millijoules each.
⚫ Japanese researchers working for Toyota have created a prototype laser that
brings laser ignition much closer to reality. The laser is a small (9mm diameter,
11mm length) high powered laser made out of ceramics that produces bursts
of pulses less than a nanosecond in duration.
⚫ The laser also produces more stable combustion so you need to put less fuel
into the cylinder, therefore increasing efficiency.
⚫ Optical wire and laser setup is much smaller than the current spark plug model,
allowing for 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.

16. Comparative Advantages of Laser
Ignition
Spark ignition system Laser ignition system
⚫ Less intense spark
⚫ Leaner mixtures cannot be
burned
⚫ Flame propagation is slow
⚫ Multi point fuel ignition is not
feasible.
⚫ It causes more NOx emission
⚫ More intense spark
⚫ Leaner mixture can burn
effectively
⚫ Flame propagation is faster
⚫ Easier possibility of multipoint
ignition.
⚫ Less NOx emission

17. Additional advantages of Laser
Ignition:
⚫ It does not require maintenance to remove carbon
deposits because of its Self cleaning property.
⚫ Precise ignition timing possible.
⚫ High load/ignition pressures possible => increase in
efficiency.
⚫ Easier possibility of multipoint ignition.

18. COMPERISION S.P AND L.I

19. Future Research Needs and
Shortcomings
⚫ Cost
⚫ Concept proven, but no commercial system yet available.
⚫ Stability of optical window
⚫ Beam Delivery/Laser induced optical damage
⚫ Particle Deposits
⚫ Intelligent control
⚫ Laser Distribution
⚫ Multiple pulse ignition
⚫ Multiple point ignition
⚫ Single Point Ignition:
⚫ Timing optimization (phasing) vs Thermal Efficiency
⚫ NOx tradeoffs
⚫ Knock margin
⚫ Multipoint Ignition:
⚫ Higher flame speed may provide additional knock margin
as well as a higher burn rate.
⚫ Multipulse Ignition:
⚫ May provide improved ignition, leaner combustion, and lower emissions.
⚫ May provide a way to circumvent beam delivery issue.

20. Summary
⚫ Laser Ignition has the potential to greatly improve
existing and future artillery systems.
⚫ Safer
⚫ Environmentally Friendly
⚫ Reliable
⚫ Automated Operation
⚫ Technology Driven System Improvements
⚫ Versatile and Flexible

21. 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.
⚫ Laser ignition is nonintrusive in nature; high energy can be rapidly
deposited, has limited heat losses, and is capable of multipoint
ignition of combustible charges.

22. REFERENCES
⚫ http://www.laserist.org/Laserist/showbasics_laser.html
⚫ Bergmann and Schaefer, Lehrbuch der Experimentalphysik:
Elektrizit¨at und Magnetismus, vol. 2, Walter de Gruyter Berlin, 1981
⚫ D. R. Lidde, ed., CRC Handbook of Chemistry and Physics, CRC Press,
2000
⚫ International Journal of Science and Research (IJSR)
Volume 3 Issue 7, July2014.
⚫ J.D. Dale, P.R. Smy, R.M. Clements, Laser Ignited Internal
Combustion Engine An Experimental Study, S.A.E. Conference in
Detroit, 29March 1978
⚫ Ma J.X., Alexander D.R., Poulain D.E., Laser spark ignition and
combustion characteristics of methane-air mixtures, Combustion
and Flame 112, 492-506 (1998).