Laser Ignition for

Combustion Engines

PRESENTED BY , GUIDED BY , BASAVARAJ BELURE. SHANT KUMAR BOCHARE

CONTENTS1. INTRODUCTION2. WHY LASER IGNITION?3. HOW LASER IGNITION WORKS4. PRINCIPLE OF LASER IGNITION5. LASER ARRAGEMENTS6. EXPERIMENTAL SETUP7. LASER SPARK PLUG8.Std. SPARK PLUG IGNITION IN AN IC ENGINE9.LI SYSTEM FOR AN IC ENGINE10.DIRECT COMPARISON LI-SPARK PLUG IGNITION11.ADVANTAGES 12.DISADVANTAGES13.CONCLUSION14.REFERENCES

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.

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.

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.

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.

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 ?

Principle of Laser Ignition

mixture burning

focused laser beam

Plasma

flame kernel

Laser Arrangement

Experimental setup

Laser spark plug

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).

Laser Ignition System for an Internal Combustion Engine

Direct comparisonlaser ignition – spark plug ignition

Laser ignition

Spark plug ignition

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.

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 .

• Fuel lean ignition possible.

Disadvantages

• High system costs.

• Concept proven, but no commercial system available yet.

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.

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.

REFERENCES

1. http://www.laserist.com2. www.studaymafia.com3. www.slideshare.com4. www.Google.com5. www.wikipedia.com

THANK YOU

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