3. Introduction
• Major problem environmental pollution is faced by today’s world.
• For which, vehicular emission is a major contributor.
• Exhaust gases from vehicles includes CO,CO2,HC,NOx etc.
• Of these NOx is particularly very harmful.
• These are one of the chief constituents of smog, which have an adverse effect on
ecological systems.
• They are also contribute to the formation of acid rain.
• NOx also cause breathing illness in human beings.
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4. Formation of NOx
• Oxygen is used to burn the fuel in the engine cylinder.
• When the peak temperatures are high enough for longer periods of
time, the nitrogen and oxygen in the air combines to form nitrogen
oxides.
• These are normally referred to as “NOx”.
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5. EXHAUST GAS RECIRCULATION
• Exhaust gas recirculation is an efficient method to reduce Nox emissions from the
engine.
• It works by recirculating a quantity of exhaust gas back to the engine cylinders.
• Intermixing the recirculated gas with incoming air reduces the amount of
available O2 to the combustion and lowers the peak temperature of combustion.
• Recirculation is usually achieved by piping a route from the exhaust manifold to
the intake manifold.
• A control valve within the circuit regulates and times the gas flow.
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10. Advantages
• It reduces the NOx emission and save the environment.
• It decreases the engine temperature.
• Improves the engine life.
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11. Disadvantages
• As EGR reduce O2 so it is difficult to combust the fuel.
• Continues reduction of O2 reduce the peak power required for the
engine.
• EGR valve can’t respond all time.
• EGR valve will take time to flow EGR gases.
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12. Conclusion
• Using EGR technique in engines, the emissions are very much
controlled due to lesser amounts of NOx entering the atmosphere.
• EGR is a very simple method. It has proven to be very useful.
• This method is very reliable in terms of fuel consumption.
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13. References:
Journal paper:
Ladommatos, N. and Abdelhalim, S.(1999). The effects of exhaust gas recirculation on diesel
combustion and emissions. International journal of Engine Research, pp. 107-125.
Journal paper:
Abd - Alla , G.H.(2001). Using exhaust gas recirculation in internal combustion engines: a review.
Engine conversion and management, pp. 1027-1042.
Text Book:
Kripal Singh, (2011), Automobile Engineering: (volume-2), Standard publisher distributors, Page
no(478-506).
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