At present, a laser ignition plug is very expensive compared to a standard electrical spark plug ignition system and it is no where near ready for deployment. But the potential and advantages certainly make the laser ignition more attractive in many practical applications
3. ITRODUCTION
1. Economic as well as environmental constraints demand further
reduction in fuel consumption and the exhaust emissions
2. Regulations on NOx emissions are pushing us toward
leaner air/fuel ratios (higher ratio of air to fuel).
3. Natural gas is more difficult to ignite than gasoline due to
the strong Carbon to Hydrogen bond energy.
4. Because of the requirement for an increase in ignition energy, spark plug
life will decrease for natural gas engines.
4. Conventional Spark Plug IC Engine
Drawbacks of Spark plug:
• Location of spark plug is not flexible as it require shielding of
plug from immense heat.
• It is not possible to ignite inside the fuel spray.
• It requires frequent maintenance and removal of carbon deposits.
• Leaner mixtures cannot be burned.
• Higher turbulence levels are required.
5. Laser Ignition system
LASER (Light amplification by stimulated emission of radiation)
What is a laser?
Laser Production
The ruby laser is a active laser medium and synthetic rod that is
energized through optical pumping, typically by a xenon flashtube.
Ruby has very broad and powerful absorption bands in the visual
spectrum, at 400 and 550 nm.
Laser is a Unidirectional monochromatic beam of light.
6. Laser Production
The Xenon flash tube continuously flashes light in to ruby rod which excites the
atoms in the ruby rod.
Some of these atoms absorbs energy and the electrons with in the atoms
excite and emits photons
7. Types of Lasers
will replace the plug see Ruby Laser
Gas Laser
Chemical Laser
Excimer Laser
Solid state Laser
Semi conductor Laser
Dye Laser
8. How Laser Ignition Works
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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:
9. Combustion Chamber Experiment
Technical data of the research engine and the Nd:YAG Laser used for the experiments
Result
Compared to conventional spark plug ignition, laser ignition reduces the fuel
consumption by several per cents nearly 20%.
Best results in terms of fuel consumption have been achieved by laser ignition
within the fuel spray and dosen’t suffer any restrictions.
10. Advantages
• Location of spark plug is flexible as it dose not require shielding from immense
heat and fuel spray i.e. Focal point can be made anywhere in the combustion
chamber
• Flame propagation is fast as multipoint fuel ignition is also possible.
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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 is
also possible here certainty of fuel presence is very high
Flame propagation is fast as multipoint fuel ignition is also possible
11. Conclusion
• The applicability of a laser-induced ignition system on direct injected gasoline
engine has been proven. Main advantages are the 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
At present, a laser ignition plug is very expensive compared to a standard
electrical spark plug ignition system and it is no where near ready for
deployment. But the potential and advantages certainly make the laser ignition
more attractive in many practical applications.
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