• 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.

• The purpose of the EGR system is to precisely regulate the flow under different operating conditions.

• By integrating the fuel and spark control with the EGR metering system, engine performance and the fuel economy can be enhanced

• For this an ECM (Electronic Control Machine) is used to regulate the EGR flow. When EGR is required ECM opens the EGR valve.

• The ECM is capable of neutralizing the negative aspects of EGR by programming additional spark advance and decreased fuel injection duration during periods EGR flow

• Using Exhaust Gas Recirculation Technique in engines, the emissions are very much controlled due to lesser amounts of NOx entering the atmosphere.

• Exhaust Gas Recirculation is a very simple method. It has proven to be very useful and it is being modified further to attain better standards.

• This method is very reliable in terms of fuel consumption

• EGR is the most effective method for reducing the nitrous oxide emissions from the engine exhaust.