This document discusses laser ignition as an alternative to spark plug ignition in combustion engines. It begins with an introduction to laser ignition and why it may be preferable to spark plugs when igniting leaner fuel mixtures or fuels like natural gas that are more difficult to ignite. It then explains how laser ignition works by focusing a laser beam to generate a high-temperature plasma that ignites the fuel-air mixture. The document presents the experimental setup used to test laser ignition and compares it directly to spark plug ignition. It concludes that laser ignition provides advantages like improved ignition of lean mixtures and longer lifetime, though challenges around cost and optical window stability remain.

1. Laser Ignition
for
Combustion Engines
PRESENTED BY , GUIDED BY ,
BASAVARAJ BELURE. SHANT KUMAR BOCHARE

2. CONTENTS
1. INTRODUCTION
2. WHY LASER IGNITION?
3. HOW LASER IGNITION WORKS
4. PRINCIPLE OF LASER IGNITION
5. LASER ARRAGEMENTS
6. EXPERIMENTAL SETUP
7. LASER SPARK PLUG
8. Std. SPARK PLUG IGNITION IN AN IC ENGINE
9. LI SYSTEM FOR AN IC ENGINE
10. DIRECT COMPARISON LI-SPARK PLUG IGNITION
11. ADVANTAGES
12. DISADVANTAGES
13. CONCLUSION
14. REFERENCES

3. INTRODUCTION
• Sustainability with regard to internal combustion engines is
strongly linked to the fuels burnt and the overall efficiency. Laser
ignition can enhance the combustion process and minimize
pollutant formation. This paper is on laser ignition of sustainable
fuels for future internal combustion engines. Ignition is the process
of starting radical reactions until a self-sustaining flame has
developed. In technical appliances such as internal combustion
engines, reliable ignition is necessary for adequate system
performance. Ignition strongly affects the formation of pollutants
and the extent of fuel conversion. This paper presents experimental
results on laser-induced ignition for technical applications. Laser
ignition tests were performed with the fuels hydrogen and biogas
in a static combustion cell and with gasoline in a spray-guided IC
Engine.

4. Continued…
A Nd:YAG laser with 6 ns pulse duration, 1064 nm
wavelength and 1-50 mJ pulse energy was used to ignite the
fuel/air mixtures at initial pressures of 1-3 MPa. Schlieren
photography was used for optical diagnostics of flame
kernel development and shock wave propagation. Compared
to a conventional spark plug, a laser ignition system should
be a favorable ignition source in terms of lean burn
characteristics and system flexibility. Yet several problems
remain unsolved, e.g. cost issues and the stability of the
optical window. The literature does not reveal much
information on this crucial system part. Different window
configurations in engine test runs are compared and
discussed.

5. 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.

6. Continued…
• 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.

7. 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.
HOW LASER IGNITION WORKS ?

8. Principle of Laser Ignition
mixture burning
focused laser beam
Plasma
flame kernel

9. Laser Arrangement

10. Experimental setup

11. Laser spark plug

12. 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).

13. Laser Ignition System for an Internal
Combustion Engine

14. Direct comparison
laser ignition – spark plug ignition
Laser ignition
Spark plug ignition

15. Advantages
• Effective ignition of leaner mixture at lower
combustion temperature.
• Less NOx emissions.
• No erosion effects in case of spark plug.
• Lifetime of laser ignition system expected to be
significantly longer than that of conventional spark
plug.
• High load ignition pressure possible.

16. Advantages (continued)
• High power output, hence higher efficiency.
• Precise ignition timing possible.
• Exact regulation of the ignition energy deposited in
the ignition plasma.
• Multipoint ignition is possible.
• Shorter ignition delay time and shorter combustion
time .

17. Disadvantages
• High system costs.
• Concept proven, but no commercial system available
yet.

18. Conclusion
• An enhanced ignition source can make a strong
contribution to sustainability in internal combustion
engines.
• It was found in the test with hydrogen that with
higher initial pressure the minimum pulse energy for
ignition decreases, same behavior was found for
methane.
• Fuel-lean biogas/air mixture exhibit a slower
combustion process which results in lower peak
pressure and flame emission compared to methane-air
of same air to fuel ratio.

19. Conclusion (Continued…)
• Applicability of the laser induced ignition as a
future ignition system for combustion engines
with spray-guided combustion process could
be proved with basic research.
• It is possible to ignite mixtures with different
laser systems.

20. REFERENCES
1. http://www.laserist.com
2. www.studaymafia.com
3. www.slideshare.com
4. www.Google.com
5. www.wikipedia.com

21. THANK YOU