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CONTENTS

• Introduction

• Drawbacks of conventional SI

• Laser

• Laser Ignition

• Advantages

• Combustion Chamber Experiment

• Results

• Conclusion

• Reference

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INTRODUCTION

• An ignition system is a system for igniting a fuel-air mixture

• The process of combustion of fuel is initiated by the ignition system

• In IC engines there are 2 types of ignition based on the fuel• Spark Ignition (petrol engine)• Compression Ignition (diesel engine)

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INTRODUCTION

• Tasks performed by ignition system:• It create a high voltage enough (20,000+) to arc across

the gap of a spark plug • It must control the timing of the spark so it occurs at the

exact right time and send it to the correct cylinder.

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DRAWBACKS OF CONVENTIONAL SPARK IGNITION

• Location of spark plug is not flexible as it require shielding of plug from immense heat and fuel spray.

• It is not possible to ignite inside the fuel spray.

• It requires frequent maintenance to remove carbon deposits.

• Leaner mixtures cannot be burned.

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DRAWBACKS OF CONVENTIONAL SPARK IGNITION

• Degradation of electrodes at high pressure and temperature.

• Flame propagation is slow.

• Multi point fuel ignition is not feasible.

• Higher turbulence levels are required.

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LASER

• Light Amplification by Stimulated Emission of Radiation

• Intense & Unidirectional beam of light

• Monochromatic & Coherent

• Main parts • Power supply• Lasing Medium• Pair of precisely aligned mirrors (100% & 96%)

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LASER GENERATION

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LASER GENERATION

Laser Crystal : Ruby

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TYPES OF LASERS

• Gas lasers

• Chemical lasers

• Semiconductor lasers

• Solid state lasers• Have lasing material distributed in a solid matrix

• Dye lasers• Use complex organic dyes, such as rhodamine 6G, in liquid

solution or suspension as lasing media.

• Excimer lasers• Use reactive gases, such as chlorine and fluorine, mixed with

inert gases such as argon, krypton or xenon.

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Laser Type  Wavelength (nm) 

Argon fluoride (UV)  193 

Krypton fluoride (UV)  248 

Xenon chloride (UV)  308 

Nitrogen (UV)  337 

Argon (blue)  488 

Argon (green)  514 

Helium neon (green)  543 

Helium neon (red)  633 

Rhodamine 6G dye (tunable)  570-650 

Ruby (CrAlO3) (red)  694 

Nd:Yag (NIR)  1064 

Carbon dioxide (FIR)  10600 

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LASER IGNITION

• Laser Ignition is the process of starting combustion by the stimulus of a laser source.

• Alternative solution to the standard spark plug is the use of pulsed laser, focused to create plasma.

• First demonstrated by J. D. Dale in 1978.

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PRINCIPLE OF LASER IGNITION

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LASER ARRANGEMENT

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COMPONENTS

• Power source

• Nd: YAG laser

• Combustion chamber window

• Optical Fibre Wire

• Focusing Unit

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FOCUSING OPTICS

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MULTIPOINT IGNITION

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MINIMUM ENERGY REQUIRED FOR IGNITION

• The minimum ignition energy required for laser ignition is more than that for electric spark ignition because of following reasons:

• The efficiency of energy transfer to near-threshold laser sparks is substantially lower than to electrical sparks, so more power is required to heat laser sparks.

• Energy in the form of photons is wasted before the beam reach the focal point.

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ADVANTAGES OF LASER INDUCED SPARK IGNITION

• It does not require maintenance to remove carbon deposits because of its Self cleaning property.

• Leaner mixtures can be burned as fuel ignition inside combustion chamber.

• Lower combustion temperatures & less NOx emissions.

• High pressure and temperature does not affect the performance allowing the use of high compression ratios.

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ADVANTAGES OF LASER INDUCED SPARK IGNITION

• Flame propagation is fast as multipoint fuel ignition is also possible.

• Higher turbulence levels are not required due to above said advantages.

• Lifetime is high.

• Shorter ignition delay time and shorter combustion time.

• Precise ignition timing possible.

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COMBUSTION CHAMBER EXPERIMENT

• Done by Institute for Internal Combustion Engines & Automotive Engineering, Vienna

• Research engine:• Q-switched Nd:YAG laser

system

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Technical data of the research engine and the Nd:YAG laser used for the experiments

Research engine   Q-switched Nd:YAG  

No. of cylinders 1 Pump source Flash lamp

No. of valves 1 Wavelength 1064 or 532 nm

Injector Multi-hole Max. pulse energy 160 mJ

Stroke 85 mm Pulse duration 6 ns

Bore 88 mm Power consumption 1 kW

Displacement vol. 517 cm 3 Beam diameter 6 mm

Compression ratio 11.6 Type Quantel Brilliant

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FLAME PROPAGATION IN COMBUSTION CHAMBER

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RESULT COMPARISON

Consumption Smoothness Emissions80

90

100

110

Spark ignition between fuel sprayLaser ignition between fuel sprayLaser ignition within fuel spray

(Perc

en

t)

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RESULTS

Self-cleaning of Beam Entrance Window

1. After 20 h operation with spark plug ignition, heavily polluted

2. Immediately after 100 laser pulses. Beam area is cleaned by the laser beam.

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NOx EMISSION POTENTIALS

Series10

50

100

150

200

250

300

350

250

190

70

330

240

Direct Pre chamber Direct Pre chamber  Spark ignition Laser ignition Diesel pilot ignition

NOx in [mg/Nm³]

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COMPARISON OF LASER IGNITION & SPARK PLUG IGNITION

For 100% ignition reliability at 30 bar

A/Frel = 2.05 (laser ignition)

A/Frel = 1.74 (spark ignition)

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CONCLUSION

• The applicability of a laser-induced ignition system on engine has been proven.

• Main advantages are the free choice of the ignition location within the combustion chamber, even inside the fuel spray. Significant reductions in fuel consumption & exhaust gases.

• At present, a laser ignition plug is very expensive comparatively.

• But potential advantages will surely bring it in to market for many practical applications.

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REFERENCE1. “Laser Ignition in Internal Combustion Engines”, Pankaj Hatwar, Durgesh Verma; International Journal of Modern Engineering Research (IJMER),Vol.2, Issue.2, Mar-Apr 2012 pp-341-345.

2. "Laser Plasma-Initiated Ignition of Engines", J. Tauer1, H. Kofler, K. Iskra, G. Tartar And E. Wintner; 3rd International Conference on the Frontiers of Plasma Physics and Technology

3. "Laser Ignition - a New Concept to Use and Increase the Potentials of Gas Engines", Dr. Günther Herdin, DI Johann Klausner, Prof. Ernst Wintner; ASME Internal Combustion Engine Division 2005 Fall Technical Conference, Ottawa, Canada.

4. http://www.iitk.ac.in/erl/laserignition.html

5. http://www.faqs.org/patents/app/20080264371

6. http://en.wikipedia.org/wiki/Ignition_system

7. http://auto.howstuffworks.com/ignition-system4.html

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THANK YOU

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