Exhaust Gas Re Circulation Presentation

8/3/2019 Exhaust Gas Re Circulation Presentation

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EXHAUST GASRECIRCULATION

By,

BHUPENDRA SINGH (08BME055)

VIJAY KUMAR PRASAD (08BME245)


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INTRODUCTION Major problem faced by todays world is environmental

pollution.

Of these vehicular traffic is a major contributor .

Exhaust gases from vehicles includes CO,CO2,HC,NOx ..

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 also contribute to the formation of acid rain.

NOx also cause breathing illness in human beings.


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FORMATION OF NOx.

The factors that cause diesel engines to run moreefficiently than gasoline engines also cause them torun at a 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 forlong periods of time, the nitrogen and oxygen in theair combines to form Nitrogen oxides.

These are normally collectively referred to as NOx.


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HOW CAN NOx BE REDUCED?

In order to reduce NOx a engine should run at a lowertemperature than the normal temperature.

Reduced cylinder temperatures can be achieved in threeways.

1. Enriching the air fuel mixture2. Lowering the compression ratio and retarding

ignition timings

3. Reducing the amount of Oxygen in the cylinder


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EXHAUST GAS RECIRCULATION

Exhaust Gas Recirculation is an efficient method toreduce NOx emissions from the engine.

It works by recirculating a quantity of exhaust gasback to the engine cylinders.

Intermixing the recirculated gas with incoming airreduces the amount of available O2 to thecombustion And lowers the peak temperature ofcombustion.

Recirculation is usually achieved by piping a routefrom the exhaust manifold to the intake manifold.

A control valve within the circuit regulates and times

the gas flow.


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Schematic Diagram of An EGR


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BASIC PARTS OF EGR There are 3 basic parts of EGR

1. EGR Valve

2. EGR Cooler

3. EGR Transfer Pipe


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TYPICAL FOUR STROKE DIESELENGINE WITH BASIC PARTS OF EGR


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EGR OPERATING CONDITIONSThere are three operating conditions for EGR flow.

1. High EGR flow

2. Low EGR flow

3. No EGR flow


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EGR THEORY OF OPERATION

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

By integrating the fuel and spark control with the EGRmetering system, engine performance and the fuel economycan be enhanced

For this an ECM (Electronic Control Machine) is used toregulate the EGR flow. When EGR is required ECM opensthe EGR valve.


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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


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EXPERIMENT RESULTS

Relationship between EGR rate and NOX


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Relationship between O2 concentration

And NOx reduction


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HC and NOx concentration as a function of

EGR Level


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Relation of PM accumulation rate

And NOx emission with EGR


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TECHNICAL ISSUES

1. Combustion Contamination Exhaust gas from any combustion process may have certaincontaminants

May lead to serious combustion degradation and instability, and

shorter component life.

2. Control System Stability Control systems for modern engines have been developed over

two decades to maintain emissions control at varying loads,speeds, and fuel conditions.

Adding EGR into the combustion process introducesfurther complexity that must be carefully integrated into theentire engine control system approach for successfuloperation over a wide range of conditions.


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3. Materials and Durability

EGR systems may decrease long-term life of thecomponents affected, including the EGR coolers andcontrol valves, the pistons and cylinder heads, exhaustmanifolds and sensors

Continuous duty applications may cause materialsbreakdown, shorter component life, and even

unexpected, catastrophic engine failures.

FUTURE OF EGR


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FUTURE OF EGR

Current Proposal:

Require a functional check of the EGR system:detect a malfunction when the system has reachedits control limits such that it cannot achieve the

target EGR flow

Require a functional check of the EGR cooling

system for proper cooling

CONCLUSION


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CONCLUSION

Using Exhaust Gas Recirculation Technique in engines, theemissions are vary much controlled due to lesser amounts ofNOx entering the atmosphere.

Exhaust Gas Recirculation is a very simple method. It hasproven to be very useful and it is being modified further toattain better standards.

This method is very reliable in terms of fuel consumption

EGR is the most effective method for reducing the nitrousoxide emissions from the engine exhaust.


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THANK YOU

Exhaust Gas Re Circulation Presentation

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