Exhaust gas recirculation

It have introduction,different parts,working,advantages,disadvantages and conclusion...

1. EXHAUST GAS RECIRCULATION Submitted By:- SANDEEP KUMAR MOHANTA 1301302009

2. INTRODUCTION Major problem environmental pollution is faced by today’s world. For which, vehicular traffic is a major contributor. Exhaust gases from vehicles includes CO,CO2,HC,Noxs 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.

3. FORMETION OF NOx The factors that cause diesel engines to run more efficiently than gasoline engines also cause them to run at higher temperature. This leads to the creation of Nitrogen Oxides ( NOx ). Fuel in any engine is burned with extra air and some of the OXYGEN is used to burn the fuel. When the peak temperatures are high enough for long periods of time, the NITROGEN and OXYGEN in the air combines to form NITROGEN OXIDES. These are normally collectively referred to as “ NOx ”.

4. HOW CAN NOx BE REDUCED? In order to reduce NOx an engine should run at a lower temperature than the normal temperature. Reduced cylinder temperatures can be achieved in three ways. Enriching the air fuel mixture 2. Lowering the compression ratio and retarding ignition timings 3. Reducing the amount of Oxygen in the cylinder

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 O 2 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.

6. BASIC PARTS OF EGR There are 3 basic parts of EGR EGR Valve EGR Cooler EGR Transfer Pipe

7. EGR VALVE

8. EGR COOLER

9. EGR TRANSFER PIPE

10. EGR ENGINE

11. WORKING PRICIPLE O2+N2 Gas In CO2,Nox,Etc out 5%-30% of NOx in to EGR EGR Valve open Mixed with O2 and enters to Engine

12. EGR OPERATING CONDITIONS There are three operating conditions for EGR flow. No EGR flow Low EGR flow High EGR flow

13. VARIATION OF BSFC WITH ENGINE LOAD

14. EXHAUST GAS TEMP Vs ENGINE LOAD

15. BRAKE THERMAL EFFICIENCY Vs ENGINE LOAD

16. ADVANTAGES It reduce Nox and save the environment. It decreases the engine temperature. Improve Engine life through reduced cylinder temperature.

17. 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 valves can’t responds all the time and it will take time to flow the EGR gases. As the amount of recirculated gas is less so for multicylinder engine the EGR gas is not reach in proper ratio.

18. CONCLUSION Using Exhaust Gas Recirculation Technique in engines, the emissions are vary 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.

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