Seminar Report 2018 Exhaust Gas Recirculation in C.I.

engines

CHAPTER 1

INTRODUCTION

Better fuel economy and higher power with lower maintenance cost has
increased the popularity of diesel engine vehicles. Diesel engines are used for
bulk movement of goods, powering stationary/mobile equipment, and to
generate electricity more economically than any other device in this size range.
In most of the global car markets, record diesel car sales have been observed in
recent years. The exhorting anticipation of additional improvements in diesel
fuel and diesel vehicle sales in future have forced diesel engine manufacturers
to upgrade the technology in terms of power, fuel economy and emissions.
In recent year due to globalization and industrial development, transportation
industries are flourishing very fast. Such industries are very much responsible for
atmospheric pollution which is detrimental to human health and environment.
Internal combustion engines are the main power source for the automobile
vehicles which is used by transportation industries. Mostly all the diesel engines
have high thermal efficiencies because of their high compression ratio and lean
air-fuel o deperation. The high compression ratio produces the high temperatures
required to achieve auto ignition and the resulting high expansion ratio makes the
engine discharge less thermal energy in the exhaust. Due to lean air-fuel mixture,
extra oxygen in the cylinders is present to facilitate complete combustion.
Increasing diesel consumption increases the pollutant that pollutes the
atmospheric air. Thus good efforts are being made to reduce the pollutants emitted
from the exhaust system without loss of power and fuel consumption. Recent
concern over development in automotive technology is the low environmental
impact. In fact, partial recirculation of exhaust gas, which is not a new technique,
has recently become essential, in combination with other techniques for attaining
lower emission levels. The development of a new generation of exhaust gas
recirculation (EGR) valves and improvements in electronic controls allow a better
EGR accuracy and shorter response time in transient condition.
Pollutants are because of the incomplete burning of the air-fuel mixture in the
combustion chamber. The major pollutants emitted from the exhaust due to
incomplete combustion are,

Carbon monoxide (CO)

Hydrocarbons (HC)

Oxides of nitrogen (NOx)

If combustion is complete, the only products being expelled from exhaust
would be water vapour which is harmless, and carbon dioxide, which is an
inert gas and, as such it is not directly harmful to humans.

CUIET 1 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

1.1 MECHANISM OF FORMATION OF POLLUTANTS

1.1.1. Carbon Monoxide (CO)

Carbon monoxide (CO) is a colourless, odourless, and tasteless gas that is slightly
lighter than air. It is toxic to humans and animals when encountered in higher
concentrations. CO is generally formed when the mixture is rich in fuel. The
amount of CO formation increases as the mixture becomes more and more rich in
fuel. A small amount of CO will come out of the exhaust even when the mixture is
slightly lean in fuel because air fuel mixture is not homogenous and equilibrium is
not established when the products pass to the exhaust. At the high temperature
developed during the combustion, the products formed are unstable and following
reactions take place before the equilibrium is established.

2C+O2 = 2CO

As the products cool down to exhaust temperature, major part of CO reacts

with oxygen to form CO2. However, a relatively small amount of CO will
remain in exhaust.

1.1.2. Hydrocarbons (HC)

Hydrocarbons, derived from unburnt fuel emitted by exhausts, engine

crankcase fumes and vapour escaping from the carburetor are also harmful to
health. Hydrocarbons appears in exhaust gas due to local rich mixture pockets
at much lower temperature than the combustion chamber and due to flame
quenching near the metallic walls. A significant amount of this unburnt HC
may burn during expansion and exhaust strokes if oxygen concentration and
exhaust temperature is suitable for complete oxidation.

1.1.3. Oxides of Nitrogen (NOx)

Oxides of nitrogen is produced in very small quantities can cause pollution.

While prolonged exposure of oxides of nitrogen is dangerous to health. Oxides
of nitrogen which occurs only in the engine exhaust are a combination of nitric
oxide (NO) and nitrogen dioxide (NO2). Nitrogen and oxygen react at
relatively high temperature. NOx is formed inside the combustion chamber in
post-flame combustion process in the high temperature region. The high peak
combustion temperature and availability of oxygen are the main reasons for the
formation of NOx. In the present of oxygen inside the combustion chamber at
high combustion temperatures the following chemical reactions will takes
place behind the flame.

N2+O2 = 2NO

N2+2H2O = 2NO+H2

CUIET 2 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

Calculation of chemical equilibrium shows that a significant amount of NO

will be formed at the end of combustion. The majority of NO formed will
however decompose at the low temperatures of exhaust. But, due to very low
reaction rate at the exhaust temperature, a part of NO formed remains in
exhaust. The NO formation will be less in rich mixtures than in lean mixtures.
The concentration of oxides of nitrogen in the exhaust is closely related peak
combustion temperature inside the combustion chamber.

1.2 NOx EMISSION CONTROL

NOx emission is closely related to temperature and oxygen content in the

combustion chamber. Any process to reduce cylinder peak temperature and
concentration of oxygen will reduce the oxides of nitrogen. This suggests a
number of methods for reducing the level of nitrogen oxides. Among these the
dilution of fuel-air mixture entering the engine cylinder with an inert or non-
combustible substance is one which absorbs a portion energy released during the
combustion, thereby affecting an overall reduction in the combustion temperature
and consequently in the NOx emission level. The following are the three methods
for reducing peak cycle temperature and thereby reducing NOx emission.

Water injection.

Catalyst

Exhaust gas recirculation (EGR)

1.2.1. Water injection

Nitrogen oxides NOx reduction is a function of water injection rate. NOx

emission reduces with increase in water injection rate per kg of fuel. The
specific fuel consumption decreases a few percent at medium water injection
rate. The water injection system is used as a device for controlling the NOx
emission from the engine exhaust.

1.2.2. Catalyst

A copper catalyst has been used to reduce the NOx emission from engine in the
presence of CO. Catalytic converter package is use to control the emission levels
of various pollutants by changing the chemical characteristics of the exhaust
gases. Catalyst materials such as platinum and palladium are applied to a ceramic
support which has been treated with an aluminium oxide wash coat. This results in
as extremely porous structure providing a large surface area to stimulate the
combination of oxygen with HC and CO. This oxidation process converts most of
these compounds to water vapour and carbon dioxide yu

CUIET 3 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

1.2.3. Exhaust gas recirculation

Exhaust Gas Recirculation is an effective method of NOx control. The exhaust

gases mainly consist of carbon dioxide, nitrogen etc. and the mixture has
higher specific heat compared to atmospheric air. Re-circulated exhaust gas
displaces fresh air entering the combustion chamber with carbon dioxide and
water vapor present in engine exhaust. As a consequence of this air
displacement, lower amount of oxygen in the intake mixture is available for
combustion. Reduced oxygen available for combustion lowers the effective
air–fuel ratio. This effective reduction in air–fuel ratio affects exhaust
emissions substantially. In addition to this, mixing of exhaust gases with intake
air increases specific heat of intake mixture, which results in the reduction of
flame temperature. Thus combination of lower oxygen quantity in the intake
air and reduced flame temperature reduces rate of NOx formation reactions.

The EGR (%) is defined as the mass percent of the recirculated exhaust
(MEGR) in the total intake mixture (Mt).

EGR (%) = (MEGR ÷ Mt) × 100

From above three methods, EGR is the most efficient and widely used system
to control the formation of oxides of nitrogen inside the combustion chamber
of I.C. engine. The exhaust gas for recirculation is taken through an orifice and
passed through control valves for regulation of the quantity of recirculation.

CUIET 4 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

CHAPTER 2

EXHAUST GAS RECIRCULATION SYSTEM

Fig 1: EGR system in a turbocharged engine

When EGR system is applied, the engine intake consists of fresh air and
recycled exhaust gas. Exhaust gases were tapped from exhaust pipe and
connected to inlet airflow passage. An EGR control valve was provided in this
pipe for EGR control. The exhaust gases were regulated by this valve and
directly send to the inlet manifold, upstream of compressor or downstream of
compressor. Sufficient distance for through mixing of fresh air and exhaust
gases were ensured. The above shown system is also called as hot EGR
because it not fitted with an EGR cooler which is used to cool the intake
mixture. A typical EGR valve is shown below.

CUIET 5 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

2.1. TYPES OF EGR SYSTEMS

2.1.1. Low pressure EGR systems

Fig 3: Low pressure EGR system

If portion of turbine outlet exhaust gas is delivered to compressor inlet through

the flow control valve then it called low pressure EGR loop. In low pressure
EGR system, a flow passage is a devised between the exhaust of super charger
turbine and the intake manifolds connected to the super charging compressor.
The flow of EGR regulated is with a throttling valve showing in Figure above.
The pressure differences generally are sufficient to drive the EGR flow of a
desired amount except during idling. If the exhaust gas is recycled to the intake
directly, the operation is called hot EGR. If the exhaust gas is recycled through
EGR cooler, the operation is called cooled EGR.

For turbocharged I.C. engine modification is done in EGR system because a

positive differential pressure between the turbine outlet and compressor inlet is
generally available. Furthermore, tailpipe pressure can be elevated by partial
throttling that ensures sufficient driving pressure for the EGR flow. The low

CUIET 6 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

pressure EGR loop is not applicable as the conventional compressor and

intercoolers are not designed to ensure the temperature of exhaust gas. This
type of loop can be used by directing exhaust from the turbine outlet to the
inter cooler outlet directly bypassing the compressor.

2.1.2. High pressure EGR systems

Fig 4: High pressure EGR system

Another method of EGR is high pressure EGR loop. In high pressure EGR
system, a flow passage is devised between the exhaust of engine (up-stream of
the turbine) and the intake manifolds of engine (downstream of the super
charging compressor).

In this system the exhaust gas is recirculated from upstream of the turbine to
downstream of the compressor or the downstream of the inter-cooler as shown
in Figure. The compressor and intercooler are therefore not exposed to the
exhaust gas. Such high pressure loop EGR system is only applicable when the

CUIET 7 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

turbine upstream pressure is sufficiently higher than the boost pressure

(compressor downstream pressure).
2.2 SCHEMATIC DIAGRAM OF ENGINE SETUP
USING EGR IN A CONSTANT SPEED DIESEL
ENGINE

Fig 5: Engine setup using EGR in a constant speed diesel

engine

This figure shows a two-cylinder constant speed diesel engine generator set.
This was chosen to study the effect of EGR. The engine is coupled with an AC
generator and the current generated is used by a resistive load bank, thus in-
turn loading the engine. An air box is provided in EGR loop to dampen the
fluctuations of the pulsating exhaust. An orifice is installed in the EGR loop to
measure the flow rate of re-circulated exhaust gas. To measure the intake air
flow rate, a laminar flow equipment (LFE) is installed. Suitable
instrumentation for measurement of temperatures at several locations is done.
Fuel consumption measurement is done using a gravimetric fuel consumption
meter. Exhaust gas emission measurements are done by raw exhaust gas

CUIET 8 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

emission analyzer. NOx emissions can be analyzed by a Chemiluminescence

Analyzer.
CHAPTER 3

COMBUSTION CHARACTERIZATION WITH HC

AND NOX EMISSIONS

Fig 6: NOx v/s HC v/s EGR%

Time-averaged HC and NOx concentrations in the raw engine-out exhaust are

shown in the Figure versus EGR level. This figure shows NOx concentration
decreasing and HC increasing with increasing EGR as would be expected.
Note the sudden increase in HC and leveling-off in NOx at approximately 45%
EGR, where there appears to be a significant shift in combustion chemistry.
This major transition is in sharp contrast to the slight changes observed in the
integrated pressure parameters, HR and IMEP. Because of the suddenness of
the emissions change at 45% EGR, it is clear that dynamic engine behavior at
or above this operating point will be highly nonlinear.

CUIET 9 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

CHAPTER 4

4. NOx REDUCTION EFFECT OF EGR

Figure below shows the typical NOx reduction effect of EGR at the mid-speed
range of the test engine. Under all load conditions, the amount of NOx
decreases as the EGR rate increases. The graph also shows that the NOx
reduction curves with the 0 % EGR point as the origin slope downward at
different angles according to the load; the higher the load, the steeper the
angle. In other words, the NOx reduction effect at the same EGR rate increases
as the engine load becomes higher.

Fig 7: Relationship between EGR rate and NOx

It is generally known that there are two reasons to reduce NOx by EGR. The
first of them is the reduction of combustion temperature. The addition of
exhaust gases to the intake air increases the amount of combustion-
accompanying gases (mainly CO2), which in turn increases the heat capacity
and lowers the combustion temperature. The second effect is the reduction of
oxygen concentration in the intake air, which restrains the generation of NOx.
Fig:8 shows the NOx emission test results as a function of the concentration of
oxygen in the intake air/EGR gas mixture. This graph shows that the NOx

CUIET 10 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

reduction rate depends mostly on oxygen concentration, and not on the engine
load or EGR rate.

Fig 8: Relationship between oxygen concentration and NOx reduction

Fig:8 shows the results of NOx emission tests conducted while varying both
the engine operating conditions and EGR rate, in which the test results shown
in Fig. 13 are merged. As in Fig:8, almost all the data are on or in a single
curve, indicating that there is a strong correlation between the oxygen
concentration and NOx reduction rate. The reason for this is thought to be as
follows: In Fig.7, the NOx reduction rate under a certain load is different from
that under another load even when the EGR rate remains the same because the
difference in load causes a difference in the amount of combustion-
accompanying gases and oxygen concentration in EGR gas, which in turn
changes the oxygen concentration in the intake gas (mixture of intake air and
EGR gas).

CUIET 11 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

CHAPTER 5

5. EFFECT OF EGR ON NOx EMISSION IN C.I

ENGINES

Exhaust gas recirculation (EGR) is a pre-treatment technique. This is the widely

used process to reduce and control the oxides of nitrogen (NOx) emissions from
diesel engines. EGR control the NOx because it lowers oxygen concentration and
flame temperature of the working fluid in the combustion chamber. The exhaust
gas displaces fresh air-entering the combustion chamber and this air displacement
lowers the amount of oxygen available for combustion in the intake mixture.
Reduced oxygen available for combustion lowers the effective air-fuel ratio.
Exhaust gases mixed with intake air increases specific heat of intake mixture,
which results in the reduction of flame temperature. Thus combination of lower
oxygen quantity in the intake air and reduced flame temperature reduces rate of
NOx formation. Engine using EGR emit lower quantity of exhaust gases
compared to non-EGR engines because part of the exhaust gas is recirculated.

5.1 CONSTANT SPEED DIESEL ENGINE

Fig 9: Effect of egr NOx emission in constant speed diesel engine.

CUIET 12 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

Diesel engines operating at low loads are generally tolerate a higher EGR ratio
because re-circulating exhaust gases contain high concentration of oxygen and
low concentration of carbon dioxide. But at higher loads, the oxygen in
exhaust gas becomes scare and inert constituents start dominating along with
increased exhaust temp. Thus as load increases, diesel engines tend to generate
more smoke because of reduced availability of oxygen. At very high EGR rate
(around 44%) NOx emission continuously drops but this high EGR rate
significantly affects the fuel economy. The degree of reduction in NOx at
higher loads is higher with same % EGR compared to part load. At the part
load, O2 is available in sufficient quantity but at high loads O2 reduces
drastically, therefore NOx is reduced more at higher loads compared to part
loads. The major influence on NOx emission is due to change in temperature
rather than O2 availability.

About 15% EGR rate is found to be effective to reduce NOx emission

substantially without deteriorating performance and emission. At higher loads,
increased rate of EGR reduces NOx to a greater extent but deteriorates the
performance and emissions. Therefore higher EGR rates can be applied at
lower loads.

5.2. ENGINE FUELLED WITH JETROPHA BIO-DIESEL

Fig10: Effect of Egr on NOx emission in engine using jetropha biodiesel

CUIET 13 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

NOx emission from engine fueled with jetropha biodiesel was found to be
comparatively higher than the engine fueled with diesel at full load and at part
load with 0% EGR operation. This is due to higher viscosity of bio-diesel
resulting in a dynamic injection advance apart from state injection advance
provided for optimum efficiency and excess oxygen present in the jetropha
bio-diesel. With 5% EGR, the NO level comes down for jetropha bio-diesel
and for diesel fuelled engine but still NO level is higher for jathropha bio-
diesel than for diesel at full load operation. For jathropha bio-diesel NO levels
were found to be increasing for load range 0-40% for 5% and 10% EGR
operation. These values were found to be higher compared to both diesel and
jetropha biodiesel without EGR because of the increased charge temperature
due to hot EGR and dynamic injection advance. NO emission from jetropha
bio-diesel at all loads for 15% EGR rate was lower compared to diesel without
EGR condition. 20 to 25 % EGR were able to reduce NO level by a large
amount but it will increases smoke, CO and HC emission. 15% hot EGR
reduces NO emission without much adverse effects on the performance, smoke
and other emissions. 15% EGR on jetropha bio-diesel was found to be
effective in reducing NO emission to values lower than that of diesel without
EGR at all loads. At full load, 15% EGR on jetropha bio-diesel was found to
be lower than that of corresponding diesel NO emission with 15% EGR.

5.3. HEAVY DUTY DIESEL ENGINE

In heavy duty DI diesel engines NOx emission decreases almost linearly with
EGR rate. NO emissions at full load remain almost constant when altering
EGR temp. A small NO emission increases only at high EGR rates. Formation
of NOx is temperature and O2 sensitive. So that the increase of EGR
temperature is compensate by the reduction of air fuel ratio. For the same EGR
rate has no significant effect on NO for all engines speeds, but small NO
emission increases only at high EGR rates with speed on the other hand. The
effect of EGR rate is slightly higher at low engine speed. Emission of NO
increases with increase of temperature of EGR (hot EGR) compared to the
cooled EGR. The increase of EGR temperature from 90°C to 240 °C results to
an increase of the mean gas temperature and the individual zone temperature
during the main combustion period and that create adverse effect on NO
emission. Because of that, in heavy duty DI diesel engine, EGR cooling is
favorable to retain the benefits of law NOx emissions without sacrificing the
engine efficiency.

CUIET 14 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

5.4. LPG FUELLED DIESEL ENGINE

Fig 11: Effect of egr on NOx emission in engine using LPG

The LPG has a low cetane number (<3). Therefore diethyl ether was added to
the LPG for ignition purpose. It will improve the cetane number (>125) and
has a low auto ignition temperature (160 °C). Exhaust gas recirculation (EGR)
is one of the most effective techniques for reducing NOx emission from I.C.
engines. EGR raises the total heat capacity of working gases in engine cylinder
and lowers the peak temperature due to high heat capacity of EGR.
The concentration of NOx in the case ofLPG operation without EGR is about 60%
less than NOx concentration in the case of diesel engine operation at any load. For
LPG engine it is observed that for all EGR percentages, the NO emission is found
slightly higher compared to LPG operation without EGR from no load to 40%
load. This is because the exhaust gas mixes with intake air and raises the inlet air
temperature slightly. This EGR will enhance the combustion rate and leading to
increased cylinder peak temperature and hence higher NO emissions in the engine
exhaust. But at higher power outputs, significant reduction in

NOx concentration particularly with 10% to 20% of EGR from 80% to 100%
load. This may be due to the fact that at higher loads as well as with higher
EGR percentages, the concentration of both CO2 and H2O present in the
intake is more. These gases absorb energy released by combustion, which

CUIET 15 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

reduces the peak combustion temperature in the combustion chamber resulting

in the reduction of NO emission. Also LPG with EGR operation exhibits lower
exhaust gas temperature particularly with high EGR percentages at higher
loads.

5.5 DIESEL ENGINE WITH HYDROGEN AS DUAL FUEL

Fig 12: Effect of egr on NOx emission in engine using hydrogen as dual fuel

Hydrogen is one of the best alternatives for conventional fuels. Hydrogen

enriched air is used as intake charges in a diesel engine adopting exhaust gas
recirculation (EGR).

The main pollutant exhausted by hydrogen fueled engine is NOx. NOx

emission from hydrogen duel fuel engine without EGR is higher than the diesel
engine. But with EGR, the NOx formation decreases with increase in the EGR.
This is mainly due to the replacement of air-fuel mixture by inert gas, which
reduces the peak combustion temperature.

CUIET 16 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

CHAPTER 6

6. EFFECTS OF EGR ON ENGINE PARTS

The physical conditions of various vital engine parts which are directly
exposed to combustion in-cylinder liner are shown in Figures. Components
working with EGR is shown on the left and without EGR on the right.

Fig 13: Carbon deposits on cylinder head

Fig 14: Carbon deposits on injector tip

CUIET 17 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

Fig15: Carbon deposits on piston crown

It can be clearly seen that carbon deposits on the various parts of the engine
operated with EGR system is significantly more than that of engine operated
without EGR. The higher carbon deposits in the EGR system seem to be
because of higher soot formation.

Wear of Piston Rings

The piston rings are one of the most important components in the engine,
which are essential for operation of the engine. Piston rings are subjected to
high thrust imposed by combustion gases. Rings are used to reduce the friction
between cylinder liner surface and the piston. They are made of very high
strength material so that they can resist high temperature and high thrust of
combustion process and at the same time have very low wear. In the engine
using EGR, top compression ring faces lowest weight loss compared to other
rings. The weight loss of top compression ring is about 0.30% of the initial
weight of ring. The oil ring faces highest amount of weight loss in the engine
using EGR. The amount of wear Is approximately 0.90% of initial weight. It
has been observed that the extent of wear of top ring in the engine using EGR
is lower than normal operating engine. The possible reason of this may be the
lower temperature of the combustion chamber of the engine using EGR.
However, the wear rate of second and third compression ring and oil ring is
comparatively higher for engine using EGR. The possible reason for this may
be presence of higher amount of soot and wear debris in the lubricating oil of
the engine using EGR.

CUIET 18 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

CHAPTER 7

7. CONCLUSION
Thus, as seen that using Exhaust Gas Recirculation Technique in engines, the
emissions are very much controlled due to lesser amounts of NOx entering the
atmosphere. Exhaust gases lower the oxygen concentration in combustion
chamber and increase the specific heat of the intake air mixture, which results
in lower flame temperatures. Thus the emission levels to be maintained are
attained by the engines.

It can be observed that 15% EGR rate is found to be effective to reduce NOx
emission substantially without deteriorating engine performance. As seen,
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 and highly reliable.
Thus EGR is the most effective method for reducing the nitrous oxide
emissions from the engine exhaust. Many of the four wheeler manufacturers
like Ford Company, Benz Motors etc used this technique to improve the
engine performance and reduce the amount of pollutants in the exhaust of the
engine.

CUIET 19 Department Of Mechanical Engg.,

Seminar Report 2018 Exhaust Gas Recirculation in C.I. engines

REFERENCES
1. Ajinkya B. Amritkar, Nilesh Badge: Effect of Exhaust Gas Recirculation
(EGR) in Internal ombustion Engine, International Research Journal of
Engineering and Technology (IRJET) volume: 03 mar-2016

2. Deepak Agarwal , Shrawan Kumar Singh , Avinash Kumar Agarwal: Effect

of Exhaust Gas Recirculation (EGR) on performance, emissions, deposits and
durability of a constant speed compression ignition engine, Applied Energy 88
(2011) 2900-2907
3-7
3. Harilal S. Sorathia, Dr.Pravin P. Rahhod and Arvind S. Sorathiya: Effect of
EGR on NOx emission in CI engines: A review study(2012), International
Journal of Advanced Engineering Research and Studies E-ISSN2249-8974

4. Bharat Namdev Kharad : Effect of exhaust Gas Recirculation on Engine

Performance and Emission on Variable Compression Ratio Engine ,
International Journal of Innovation in Engineering research and Technology
(IJIERT) ICITDCEME’15 conference proceedings ISSN No-2394-3696

5. Ming Zheng , Graham T. Reader , J. Gary Hawley : Diesel engine exhaust

gas recirculation––a review on advanced and novel concepts, Energy
Conversion and Management 45 (2004) 883-900

CUIET 20 Department Of Mechanical Engg.,