an experimental study of performance and emission on

AN EXPERIMENTAL STUDY OF PERFORMANCE AND EMISSION ON ETHANOL FUELLED PRE AND POST INJECTION IN HIGH COMPRESSION IGNITION ENGINE

WITH ZIRCONIA COATING

Velliangiri Murugasen Assistant professor

Coimbatore Institute of Technology Coimbatore Tamilnadu

India

Sureshkannan Gurusamy Assistant professor


India

Krishnan Annur Srinivasan Associate professor


India

ABSTRACT The research article presented here mainly focuses on

the influence of pre and post-injection (split in to three

injections) technique that was used to improve the ethanol fuel

combustion in compression ignition mode (CI), with and

without zirconia surface coating. Combustion simulation results

and experimental results were investigated and compared with

different experimental conditions. This research was used (95%

Ethanol +5% water) as a fuel in a four stroke single cylinder

variable compression ratio (VCR) engine. The VCR engine was

used to optimize compression ratio (28.8:1) and conducted

various experiments. Performance and exhaust emissions of

NOx, CO and HC were compared with ethanol fuel split

injection mode, single injection mode and diesel fuel mode.

Brake thermal efficiency of pre and post injection mode was

better than direct injection (DI) ethanol mode. The VCR engine

operating with ethanol fuel split injection mode showed peak

brake thermal efficiency (BTE) of 29%, which is nearly

operating range in the baseline diesel engine. Ethanol fuel was

mixed with 3% castorene R40 (lubrication oil) oil by volume

due to fully soluble in alcohol fuels. It was used both air and

liquid cooled engines running on methanol and ethanol fuel. Pre

and post ethanol injection mode was 54.4 % reduction of

Oxides of nitrogen (NOx) compared with single injection mode

of operation. In comparison of diesel mode operation with

zirconia coating was 3.8% increased than without coating.

KEYWORDS – Ethanol Direct injection - pre and post

Injection – Zirconia coating - high compression ignition –

Experimental investigation- performance and emission-

simulation.

NOMENCLATURE BMEP Brake Mean Effective Pressure

NOx Oxides of nitrogen

IMEP Indicated Mean Effective Pressure

LHR Low Heat Rejection engine

TFC Total Fuel Consumption

SFC Specific Fuel Consumption

Wnet Work output

BP Brake Power

IP Indicated Power

BTE Brake thermal efficiency

ITE Indicated thermal efficiency

ME Mechanical efficiency

UHC Unburned Hydrocarbon

CO Carbon Monoxide

CI Compression Ignition

PSZ Partially Stabilized Zirconia

PM Particulate Matter

BSFC Brake Specific Fuel Consumption

E SIM Ethanol fuel simulation

E EXP Ethanol fuel experimental

CR Compression ratio

VCR Variable compression ratio

1.0 INTRODUCTION Petroleum fuel energy conservation and diversification

of sources of energy, which resulted from the initial sharp

increase in the price of crude oil in the early 2000, served as a

stimulant for research on all aspects of use of non-fossil fuels

for internal combustion engines. Alcohols, especially ethanol

and methanol, comprise one group of alternative fuels which is

1 Copyright © 2014 by ASME

Proceedings of the ASME 2014 International Mechanical Engineering Congress and Exposition IMECE2014

November 14-20, 2014, Montreal, Quebec, Canada

IMECE2014-36479

considered attractive for this purpose. Both ethanol and

methanol can be produced from indigenous energy resources

like biomass, coal and natural gas. Nowadays, the extinction

usage of fossil fuel due to continuous usage becomes the focus

attention for all the people in the world who depend on this

energy source in every activity.

The researchers attention is focused on fossil fuel due

to the fact that continuously usage of this fuel believed causing

environment problem i.e., air pollution and global warming.

Hence IC engine researchers all over the world have been trying

to look for a solution by exploring and using an alternate fuel,

which is environmental friendly and sustainable availability.

Compression ignition (CI) engine has higher thermal efficiency

and produces higher power that can save more fuel compared to

gasoline engine [1]. Therefore, diesel engines are usually used

on large buses, trucks, heavy duty equipments, agricultural

equipments and industrial machineries. However, diesel engines

also produce gaseous pollutants such as carbon monoxide (CO),

carbon dioxide (CO2), sulphur oxides (SOx), nitrogen oxides

(NOx), unburned hydrocarbons (HC), and particulate matter

(PM) [1-3]. Until now diesel fuel is usually derived from fossil

fuel, therefore alternative fuels are needed to replace fossil

based fuels, for both reducing the consumption of fossil fuels

and pollutants in the exhaust gases.

The heat transfer can be minimized by reducing the

heat transferred from combustion chamber to the pistons. This

leads to the idea of insulating the piston and cylinder walls.

These types of engines are known as Low Heat Rejection

(LHR) engines. This can be realized by zirconia coating the

pistons, cylinder walls with ceramics which can withstand high

thermal stresses. The piston heat flux is reduced due to low

thermal conductivity which reduces heat lost by the coolant.

When cylinder cooling losses were reduced, more of the heat

was delivered to the exhaust system. Thus, efficient recovery of

energy of the exhaust improves the thermal efficiency of a low

heat rejection engine.

1.2 PARTIALLY STABILIZED ZIRCONIA (PSZ) Partially stabilized Zirconia is a mixture of zircona

polymorphs, because insufficient cubic phase-forming oxide

(Stabilizer) has been added and a cubic plus Meta stable

tetragonal ZrO2 mixture is obtained. A smaller addition of

stabilizer to the pure zirconia will bring its structure into a

tetragonal phase at a temperature higher than 1,000°C, and a

mixture of cubic phase and monoclinic (or tetragonal)-phase at

a lower temperature. Therefore, the partially stabilized zirconia

is also called as Tetragonal Zirconia Polycrystalline

(TZP). Usually such PSZ consists of larger than 8 mol% (2.77

wt %) of MgO, 8 mol% (3.81 wt %) of CaO, or 3-4 mol% (5.4-

7.1 wt %) of Y2O3. PSZ is a transformation-toughened material.

The Micro crack is depending on difference in the thermal

expansion between the cubic phase particle and monoclinic (or

tetragonal)-phase particles in the PSZ. Coefficient of thermal

expansion for the monoclinic form is 6.5-6

/°C. The cubic form is

10.5-6

/°C up to 1200°C. This difference creates micro cracks

that dissipate the energy of propagating cracks. The induced

stress explanation depends upon the tetragonal-to-monoclinic

transformation, once the application temperature over pass the

transformation temperature at about 1000°C. The pure zirconia

particles in PSZ can metastabily retain the high-temperature

tetragonal phase. The cubic matrix provides a compressive

force that maintains the tetragonal phase. The stress energies

gained from propagating cracks, due to the transition from the

meta stable tetragonal to the stable monoclinic zirconia. The

energy was used by this transformation is sufficient to slow or

stop propagation of the cracks. Partially Stabilized Zirconia has

been used where extremely high temperatures are required.

The low thermal conductivity (about 8 Btu/ft2/in/°F at

1800°F) ensures low heat losses, and the high melting point

permits stabilized zirconia refractory’s to be used continuously

or intermittently at temperatures of 2,200°C (4000°F) in neutral

or oxidizing atmospheres. Above 1,650°C (3000°F), in contact

with carbon, zirconia is converted in to zirconium carbide. The

photographic view of Zirconia coated piston is shown in fig 25.

2.0 LUBRICATION Compression ignition (CI) engines are used on diesel

fuel injection equipments. Injection systems were lubricated by

the fuel itself. When ethanol fuel was substituted for diesel, the

lubricant must be supplied within the fuel to provide lubrication

of the fuel injection pump and injector.

The lubricant chosen has to be miscible with the fuel.

Ethanol fuel was mixed with 3% by volume of castorene R40

was used. Castorene R40 is a Castor oil based blend

incorporating synthetic lubricants and additives which enhance

the castor oils, naturally high film strength and resistance to

seizure. This enhancement represents significant advance in

lubrication containing vegetable oil and minimizes the risk of

thickening or lacquer formation. Lubrication oil was fully

soluble in alcohol fuels and ideally suited for use in both air and

liquid cooled engines running on methanol and ethanol fuel.

Ethanol Fuel properties are shown in Table-1

Table: 1- Ethanol Fuel Properties Chemical formula of ethanol C2H5OH

Molecular weight of ethanol 46.0

Composition of ethanol by weight

Carbon 52.0%

Hydrogen 13.0%

Oxygen 35.0%

Specific gravity at 15.5 oC 0.794

Boiling point oC 78.0

Latent heat of vaporization in kJ/kg 900

Vapor pressure at 58 0C in bar 0.21

Lower calorific value in kJ/kg 27,880

Mixing heating value in kJ/kg 2970

Stoichiometric air/fuel ratio 9.0

Ignition limit Air/ fuel ratio 3.57 to17


Self ignition temperature 420 oC

Cetane number 11

Octane numbers 102

(a) For Research 111

(b) For Motor 94

3.0 IMPLEMENTATION OF MATHEMATICAL MODELS FOR PRACTICAL CALCULATIONS

Diesel RK-model was used for multi fuel

thermodynamic combustion simulation, predicts performance

and emission parameters. Thermodynamic simulation software

DIESEL-RK was intended for calculation and optimization of

the super and turbocharged internal combustion engines.

This simulation tool was (version of the DIESEL-RK

is 4.1.3.189 (June 2012)) different from analogues. RK-

model was used for mixture formation, combustion in different

fuels in CI and SI engines and also the tool was used for multi-

parameter optimization. Main features of DIESEL-RK are

similar to known thermodynamic programs.

The DIESEL-RK has new advanced applications

which are absent in other programs. DIESEL-RK was oriented

on diesel combustion optimization, fuel injection analysis and

optimization. It was used for simulation and optimization of

piston bowl shape, injector design and location. Shape of

injection profile and multiple injections (split injections)

parameters were analyzed.

The RK-model was accounted for fuel drop sizes,

interaction of free sprays with swirl spray, and wall

impingement, evolution of near-wall flow formed by spray, hit

of fuel on cylinder head surface, hit of fuel on cylinder liner,

effect of piston motion and swirl intensity on heat release rate.

A precise description of the combustion process is

important in modeling the formation of harmful substances in

the cylinder. For example, the error in determining the

temperature in the cylinder 80-90K leads to a change in the

calculated NOx output by 30%, error in determining the

temperature of 190 K change in the calculated NOx output was

2.7 times [19]. Obviously, using the proposed mathematical

simulation tool rather than empirical or semi empirical models

provide a more accurate calculation and formation of harmful

substances in the diesel engine cylinder.

Simulation was concluded that the developed Diesel

Rk tool was allowed not only to describe the dynamics of heat

generation with sufficient accuracy, but also to adequately

respond to changes in design and adjustments in the parameters

of diesel and ethanol fuel combustion chamber. Pre and post

injection profile is shown in fig 2. Thermodynamic simulation

tool was used to predict NOx generation for every cycle in

ethanol and diesel pre and post injection mode.

3.1 SIMULATIONS OF ETHANOL FUEL CI COMBUSTION WITH VARIOUS COMPRESSION RATIOS

The multi-zone RK-model was used for ethanol fuel

combustion, injection parameter optimization, fuel injection

profile prediction, account of exhaust gas recirculation (EGR),

temperatures of piston and cylinder head and heat release rate

computation.

Fig: 1 Injection velocity Vs crank angle (Diesel RK software -

Ethanol Fuel injection profile, single injection, BP 1.1929 kW)

The model allowed to prediction of heat release rate,

single and split injection mode, NOx and smoke for the VCR

engine. Simulation tool was used to predict pressure Vs crank

angle, heat release curve, compression ratio and optimization

of diesel and ethanol fuel.

It can be seen that the proposed mathematical model

provides a satisfactory agreement between the simulated and

experimental data in a wide range and different load conditions.

Fig 1, injection velocity Vs crank angle profile, indicated that

the injection velocity reaches maximum after start of injection 4

deg and duration of injection is 27 deg.

From fig 2, it is shown that injection velocity increases

and decreases with crank angle. Injection velocity reaches at

maximum after start of injection 3 deg and duration of injection

split in to three injections.

The injection quantity was divided in to three parts.

Out of three pre and post injection quantity was equal and

second part of injection was grater then first part. The

simulation was used to predict split injection performance and

injection profile.


Peak Injection velocity = 26 m/s, x axis – crank angle (deg)

Fig: 2 Pre and post fuel injection profile (split injection-rpm -

1500)

Fig : 3 Combustion Chamber Parameters (compression ratio –

28.8:1 )

From fig 3, it is shown, combustion chamber

parameters. The piston bowl was represented as a solid of

rotation with an axis that was parallel to the cylinder axis. On

the right sketch the piston bowl given by the current basic data

was displayed. The view of this piston bowl dynamically

changes at editing basic data. The sketch was given for the

modern piston bowl; the set of basic data makes it possible to

carry out calculation of engines with spherical piston bowl and

piston. Diesel RK thermodynamic simulation tool used for

predict pressure Vs crank angle diagram for ethanol fuel high

compression (28.8:1) high pressure injection (single injection

and split injection mode).

Fig: 4 Injection parameters of combustion simulations (split

injection mode)

In the fig 4, fuel injection parameters, number of

injectors, distance between spray center and bowl axis were

shown. Distance between spary center and cylinder head plane

was used 2.03 mm. This simulation used 6 hole injector and all

sprays were identical.

Fig: 5 Pressure Vs Crank angle (Ethanol fuel single Injection

angle of injection BTDC-15 deg -rpm 1500.)

Diesel RK thermodynamic simulation tool used for

predict pressure Vs crank angle diagram for ethanol fuel high

pressure injection (single injection mode). From the fig 5 show

that, the combustion simulation was used fuel injection angle

before top dead center (BTDC) -15 deg and cylinder peak

pressure was predicted with variable load conditions. The

maximum peak pressure 128 bar was attained at after TDC 110.

Compression ratio 28.8:1 was used for simulation and predicted

in cylinder peak pressure.

Crank Angle, deg


Fig: 6 pressure Vs crank angle (Ethanol fuel mode simulation

using variable injection angle before TDC 17 T0 29 Deg, CR –

28.8:1, rpm - 1500)

From the fig 6, it is shown that the combustion

simulation in cylinder peak pressure was increased with

increasing compression ratio with constant load conditions and

fuel injection varies from BTDC 17 T0 29 Deg (CR – 28.8:1).

The maximum cylinder peak pressure 142 bar was attained at

after TDC 110. Pressure Vs crank angle diagram was used to

predict and optimized injection angle was implemented in

experimental.

Fig: 7 Pressure Vs crank angle (variable compression Ratio

range 24 t0 28.7)

From the fig 7, it is shown that the in cylinder peak

pressure was increased with increasing compression ratio

(variable compression Ratio range 24 to 28.8:1) with constant

load and speed. The maximum peak pressure 138 bar was

attained at after TDC 110.

Fig: 8 Concentration of NOX (ethanol fuel single injection mode

simulation results - variable injection angle variable injection

angle BTDC 17 T0 26 Deg- CR – 28.8:1, rpm- 1500)

From the figure 8, it is shown that NOx was increased

with increasing fuel injection angle before top dead center

(BTDC 17 T0 26 Deg, CR – 28.8:1) Ethanol single injection

mode simulation at maximum load condition (BTDC 17 T0 26

Deg-CR – 28.8:1) was started from 2000ppm to 6000ppm. It

was clear that ethanol fuel single injection angle was (17 deg)

optimized for reduction of NOx emission.

Fig: 9 - Operating mode data (simulation data sheet)

The fig 9 shows engine parameters viz, engine bore,

piston stroke, compression ratio, basic engine mechanism

design data, and connecting rod length. This base data was used

to simulate combustion and emission parameters.


Fig: 10 Concentration of NOx (Ethanol fuel simulation results

pre and post injection- rpm -1500)

From the figure 10 show that NOx was increased with

increasing load conditions. Ethanol fuel pre and post injection

mode simulation at maximum load condition was 900 ppm. It is

clear that ethanol fuel Pre and post injection mode was 54.4 %

greater reduction of oxides of nitrogen than single injection

mode. Pre and post injection mode was low temperature

combustion to compare single injection combustion mode. It

was concluded that NOx formation rate was reduced in split

injection mode of operation.

Fig: 11 Heat release Rate (j/deg ) Vs crank angle (ethanol fuel

mode simulation variable injection angle BTDC 17 T0 29 deg

CR – 28.8:1, rpm -1500)

The figure 11 shows heat release rate Vs crank angle,

in which, heat release rate was increased with increasing fuel

injection angle before top dead center (BTDC 17 T0 39 Deg-

CR – 28.8:1).

Fig: 12 Heat release Rate j/deg (simulation pre and post

injection)

The figure 12 shows, pre and post injection heat

release rate Vs crank angle simulation results. Heat release rate

was split in to three peaks, first peak was at 350 deg, second

peak was attained at 365 deg and third peak was attained at 385

deg. It was increased with increasing different load conditions.

Fig: 13 Heat release Rate j/deg comparison of ethanol single

and split injection mode simulation (angle of injection BTDC

17 CR – 28.8:1)

The figure 13 shows, simulation results of single

injection and split injection heat release rate Vs crank angle.

Split injection heat release split in to three peaks, first peak was

at 350 deg, second peak was attained at 365 deg and third peak

was attained at 385 deg. It was increased with increasing

different load conditions. Pre and post injection mode was low

temperature combustion than single injection combustion mode.


Fig : 14 pressure Vs creank angle comparison of ethanol single

and split injection.

The fig 14 shows the experimental comparison of

ethanol single and split injection in-cylinder pressure.

Combustion simulation data was used to predict peak pressure.

Cylinder peak pressure was increased with single injection

mode of simulation compare with split injection. The maximum

peak pressure of split injection mode was 124 bar attained at

after TDC 120. It was clear that split injection was low

temperature combustion.

4.0 DIESEL ENGINE COMBUSTION SIMULATION AND SINGLE AND SPLIT INJECTION The multi-zone RK-model was used for diesel fuel

combustion, injection parameter optimization, fuel injection

profile prediction, account of exhaust gas recirculation (EGR),

temperatures of piston bowl, cylinder head and heat release rate

computation. The model was allowed prediction of heat release

rate, single and split injection mode, NOx and smoke for the

VCR engine. Simulation tool was used to predict pressure Vs

crank angle, heat release rate curve, and compression ratio

optimization for diesel fuel. Detail Kinetic Mechanism for

correct prediction of NOx emission in CI engine with split

injection and single (199 reactions, 33 species). Detail Kinetic

Mechanism (DKM) is supported by the local release of

DIESEL-RK. It is known the "prompt" NOx have a large effect

at low combustion temperature (multiple injections, HCCI, in

ethanol fuel and diesel fuel, etc.). Reaction of "prompt" NO

formation is used by the equation 1 and 2.

CH + N2 = HCN + N. (1)

After HCN transmit into NOx with some delay using the

equation scheme.

HCN → CN → NH → HNO → NO. (2)

Current concentrations of CH radical (1) are calculated by use

the Detail Kinetic Mechanism (DKM) of combustion process.

Detail Kinetic Mechanism consists of two parts, first part

Kinetic of first breakup of fuel molecules consists of 40

reactions with 10 species and second part Detail kinetic

mechanism of ethanol oxidation and NO formation consists of

199 reactions with 33 species.

Fig; 15 Pressure Vs crank angle simulation (diesel fuel split

injection mode CR – 17.5 – rpm 1500)

As shown in fig 15, diesel fuel combustion simulation

in cylinder peak pressure was increased with increasing load

conditions. The maximum peak pressure 82 bar was attained at

after TDC 120. Indicator diagrams derived from the cylinder

pressure data offer detailed into the combustion process and

allow the drawing of conclusions regarding the process of

combustion.

Fig; 16 Experimental Pressure Vs crank angle( diesel fuel split

injection mode CR – 17.5,rpm-1500)

The fig 16 shows experimental comparison of diesel

split injection in-cylinder pressure with different load

conditions. Experimental data were used to predict peak

pressure. Cylinder peak pressure was increased with increasing

load. The maximum peak pressure of single injection mode was

68 bar attained at after TDC 120. It was clear that diesel split

injection was low temperature combustion.

From the figure 17 it is shown that diesel fuel

combustion simulation NOx emission was increased with

increasing brake power. Single injection mode simulation

compression ratio is 17.5, from low load to maximum load

condition was shown that 410ppm to 2000 ppm. Diesel fuel


Combustion simulation NOx results were increased with

increasing load conditions.

Fig: 17 Concentration of NOx (single injection mode simulation

-diesel fuel - compression ratios -17.5:1,rpm 1500)

Fig: 18 Concentration of NOx (simulation diesel mode pre and

post injection cr -17.5:1)

As shown in figure 18, diesel fuel split injection

combustion simulation, NOx was increased with increasing

brake power. Single injection mode, NOx emission simulation

compression ratio 17.5 was used. Simulation results from low

load to maximum load conditions are compared ( 410ppm to

1450 ppm). Diesel fuel Split injection mode simulation was

used same compression ratio. (Compression ratio 17.5) From

low load to maximum load condition was compared.( 610 ppm

to 910 ppm). It is clear that diesel fuel split injection mode NOx

was decreased than single injection mode.

Y- Axis – Heat release rate J/deg

Fig: 19 Heat release rate J/deg simulation Results (diesel fuel

single injection. (CR – 17.5: 1)

The figure 19 shows heat release rate Vs crank angle

simulation results using diesel fuel with different loads. Heat

release rate was increased with increasing load conditions.

Maximum heat release (148 j/deg) was attained at 358 deg.

5.0 EXPERIMENTAL TEST AND INSTRUMENTATION.

The experimental engine was single cylinder variable

compression ratio (VCR) research engine water cooled, direct

injection and modified split injection diesel engine. Single

cylinder diesel engine is used throughout the world (including

developing countries) for small scale power generation, grain

milling, on construction sites and for pumping duties. Its rugged

construction in cast iron with forged steel crankshaft and

connecting rod, replaceable shell bearings and aluminum piston

makes it an ideal research engine. Water cooling enables

relatively easy access for temperature and pressure

measurements in the cylinder. Power may be taken off either

end of the crankshaft or at half speed off the camshaft. Table 2

gives the original specifications of the standard engine.

5.1 COMPUTERISED DATA ACQUISITION SYSTEM

The computerized data acquisition system was used to

measure and acquire in-cylinder pressure. Indicator diagrams

derived from the cylinder pressure data offer detailed insight

into the combustion process and allow the drawing of

conclusions regarding the process of combustion.

Table: 2- Research engine data


Make Research engine

No of cylinder One

Type of cooling Water

Ignition Compression ignition

Bore 87.5mm

Stroke 110 mm

Compression ratio 17.5: 1

Speed 1500 rpm

Brake power 4.9 kw

5.2 PRESSURE SIGNAL Pressure transducers are widely used in engine

research for acquisition of in-cylinder pressure data. For this

study a Kistler - type 6123 AI (Serial No. SN 370721) air

cooled piezoelectric pressure transducer was used. The small

transducer output charge was converted and amplified to a

pressure proportional voltage signal using a Kistler charge

amplifier .which is basically a charge-voltage converter. After

amplification the signal was fed into a 12 bit Analog to Digital

converter which digitizes the amplitude of the measured signal.

6.0 EXPERIMENTAL SETUP The experimental setup used in this study is shown in

fig 20. The experimental work was conducted on four stroke

single cylinder VCR split injection setup, water cooled, and

(DI) direct injection engine coupled on an eddy current

dynamometer. For measuring BP, exhaust temperature, NOX,

CO, CO 2 and Unburned HC level was measured in the exhaust

pipe. The engine exhaust temperature was measured using

digital chromel -alumel thermocouple.

The NOX level was measured using NOX analyzer. The

carbon monoxide and unburned hydrocarbon was measured by

using infrared analyzer. Fuel consumption was measured with

the help of burette and digital stop watch. The experiments were

conducted at various loads from no load to full load with and

without coated piston with different fuels. (Wet ethanol, diesel).

7.0 ENGINE MODIFICATION The selected engine was variable compression ratio

(VCR) diesel engine. The specifications and technical details of

the research engine are shown in table 2. The engine is water

cooled and single cylinder vertical engine. The engine is

mounted on a sturdy concrete bed to withstand the dynamic

forces and vibrations produced. The required compression ratio

and pre and post injection setups were provided with

modifications.

7.1 EXPERIMENTAL TEST DESCRIPTION The experimental engine was designed for this work was

derived from the single cylinder VCR diesel engine, modified

suitably to accommodated pre and post injection (split

injection) electronic control module (ECU). The experiment tests were conducted using ethanol fuel

and diesel fuel with the compression ratio from 17:1 to 29.4:1.

The experimental results were reported and discussed. The

purpose of the computerized data acquisition system was used

to measure and acquire cylinder pressure. Indicator diagrams

derived from the cylinder pressure data offer detailed insight

into the combustion process and allow the drawing of

conclusions regarding the process of combustion itself.

Experimental set up was used to measuring and acquiring

cylinder pressure data. It consists of a pressure transducer, a

crankshaft encoder giving the basis for pressure measurements

and a measuring system for storing and evaluating the pressure

signals. Four different types of fuel injectors were evaluated for

measured engine brake thermal efficiency as well as spray

characteristics with Ethanol fuel.

Fig: 20 Computerized Data Acquisition System VCR Engine

Experimental setup.

8.0 RESULTS AND DISCUSSION The experimental and simulation results were

compared and discussed various load conditions, single and

split injection mode of operations. Unburned hydrocarbon

(HC), carbon monoxide (CO), oxides of nitrogen (NOx), total

fuel consumption (TFC), specific fuel consumption (SFC),

brake thermal efficiency (BTE) of the research VCR engine

operating with ethanol fuel and base line engine results were

compared and discussed.

The high pressure direct injection diesel mode and pre

and post injection mode experimental results were compared for

performance and Emissions with Coating and without coating.

8.1 UNBURNEDHYDROCARBON EMISSIONS

From the fig 21, it is clear that, 10% of unburned

hydrocarbon emission was reduced in pre and post injection

mode than ethanol fuel single mode of operation. Experimental

mode ethanol (pre and post injection mode) HC emission


slightly increased than simulation. Ethanol pre and post

injection with coating mode slightly decreased than without

coating experimental mode.

E SIM-Ethanol simulation, E EXP- Ethanol Experimental,

DIESEL EXP – Diesel Experimental mode

Fig: 21 HC Vs BP Comparison at Constant Speed Mode ( rpm -

1500 )

The ethanol fuel has sufficient amount of oxygen, due

to that unburned hydrocarbon (HC) emission is reduced. As a

result of this, the HC will split into H and C which mixes with

O2, thereby reducing the HC emissions both pre and post

injection and single injection mode. Experimental observation

for diesel mode with coating is 4.2% reduced than without

coating.

8.2 CO EMISSIONS In fig 22, different modes of experimental and

simulation results were compared and discussed. It is clear that

CO was decreased with zirconia coating due to the complete

combustion. The carbon monoxide, which arises mainly due to

incomplete combustion. It is a measure of combustion

efficiency.

Generally, oxygen availability of ethanol was high,

due to that carbon easily combines with oxygen and reduces the

CO emission. It was observed that pre and post injection 40.2%

CO emissions were less than baseline diesel engine. Diesel with

coating and without coating results are compared and shown.

Ethanol fuel simulation and experimental results are compared.

Fig: 22 CO Vs BP Comparison at Constant Speed Mode (RPM-

1500)

Fig: 23 NOx Vs BP Comparison at Constant Speed Mode (rpm-

1500)

From the fig 23, it is shown that the NOx was

increased with increased load conditions at all test conditions.

Diesel injection without coating slightly decreased compare to

with zirconia coating. Ethanol single injection mode with

zirconia coating slightly increased with compare to without

coating. Ethanol split injection mode with coating NOx

emission was decreased compare to single injection with

coating mode. From the fig. 10 shows that simulation of NOx

range from 400 to 820 ppm. It was clear that ethanol fuel Pre


and post injection mode was a 54.4 % greater reduction of

oxides of nitrogen than single injection mode. In comparison of

Diesel mode operation with coating is 3.8% increased than

without coating.

8.3 BRAKE THERMAL EFFICIENCY From the fig 24 it is shown that brake thermal

efficiency of zirconia coated ethanol fuel pre and post injection

mode was 5.3% increased than single injection. Brake thermal

efficiency was increased due to reduction of heat loss to

surroundings from the engine.

Fig: 24 BTE Vs BP Comparisons of Constant Speed Mode

(rpm-1500) and variable load mode.

Ethanol fuel was also favorable compared to that of

the baseline diesel engine. Maximum ethanol mode simulation

BTE (34%) of pre and post injection mode operation was

achieved.

Fig: 25 Zirconia coated piston (Research Engine piston)

.

Fig: 26 Photographic view of modified piston

9.0 CONCLUSION The present engine, optimized compression ratio for

alcohol fuels, exceeds the performance of current conventional

fueled engines, and has potential as a lower-cost alternative to

the diesel.

Brake Thermal Efficiency of Zirconia coated ethanol

fuel pre and post injection mode was 5.3% increased

than single injection mode.

Emissions of NOx, CO and HC using a conventional

engine were shown to be extremely low with ethanol

mode

VCR ethanol fuel Pre and post injection mode engine

was 54.4 % greater reduction of oxides of nitrogen

than single injection mode due to low temperature

combustion to compare with single injection

combustion mode.

In comparison of Diesel mode operation, with coating

was 3.8% increased than without coating.

The unburned hydrocarbon emission is 10.2 % reduced

in pre and post injection (with coating) than ethanol

fuel single mode of operation. Pre and post injection

mode was better combustion than single injection.

Brake thermal efficiency with ethanol fuel is also

favorable compared to that of the baseline diesel

engine. In comparison of Diesel mode operation, with coating

NOx was 3.8% increased than without coating. Maximum ethanol mode BTE was 29 % of pre and

post injection mode operation was achieved by

experimental method.

10 .0 ACKNOWLEDGMENTS

The authors express their deep gratitude to the

management of Coimbatore Institute of Technology for

providing the necessary facilities for carrying out the

experiments. The authors would like to thank in particular,

beloved Correspondent Dr. S. R. K. Prasad, Secretary Dr. R.

Prabhakar, and our Principal Dr. V.Selladurai who have been

constantly encouraging and supporting us in this research.


REFERENCES [1]. Kuleshov, A. S., 2006, “Use of Multi-Zone DI Diesel Spray

Combustion Model for Simulation and Optimization of

Performance and Emissions of Engines with Multiple

Injection”, SAE Paper No 2006-01-1385.

[2]. Kuleshov, A.S., 2007, “Multi-Zone DI Diesel Spray

Combustion Model and its application for Matching the Injector

Design with Piston Bowl Shape”, SAE Paper No 2007-01-

1908.

[3]. A. Kuleshov and K. Mahkamov, 2008, “Multi-zone diesel

fuel spray combustion model for the simulation of a diesel

engine running on biofuel” , Proc. Mechanical Engineers, Vol.

222, Part A, Journal of Power and Energy, pp. 309 – 321.

[4]. Zeldovich Ya. B., and Raizer Yu.P., “Physics of shock

waves and high-temperature hydrodynamic phenomena”,

Moscow: Nauka.

[5] M. N. Nabi, et al., 2000, “Ultra Low Emission and High

Performance Diesel Combustion with Highly Oxygenated

Fuel”, SAE Paper 2000-01-0231.

[6.] N. Miyamoto, et al., 1998, “Smokeless, Low NOx, High

Thermal Efficiency, and Low Noise Diesel

Combustion with Oxygenated Agents as Main Fuel, SAE Paper

980506, 1998.

[7]. R. Baranescu, et al., 1989, “Prototype Development of a

Methanol Engine for Heavy-Duty Application-

Performance and Emissions”, SAE Paper 891653.

[8] .B. Dhaliwal, et al., 2000, “Emissions Effects of Alternative

Fuels in Light-Duty and Heavy-Duty Vehicles”, SAE Paper

2000-01-0692.

[9]. N. D. Brinkman, 1977, “Effect of Compression Ratio on

Exhaust Emissions and Performance of a Methanol- Fueled

Single-Cylinder Engine”, SAE Paper 770791.

[10]. P. Mohanan, and M. K. Gajendra Babu, 1991, “A

Simulation Model for a Methanol-Fueled Turbocharged

Multi- Cylinder Automotive Spark Ignition Engine”, SAE

Paper 912417.

[11]. T. Ryan, and S. Lestz, 1980, "The Laminar Burning

Velocity of Isooctane, N-Heptane, Methanol, Methane and

Propane at Elevated Temperatures and Pressures in the Presence

of a Diluent", SAE Paper 800103.

[12].V. Battista, et al., 1990, “Review of the Cold Starting

Performance of Methanol and High Methanol Blends in Spark

Ignition Engines: Neat Methanol”, SAE Paper 902154.

[13]. K. Hikino, T. Suzuki, 1989, “Development of Methanol

Engine with Autoignition for Low NOx Emission and Better

Fuel Economy”, SAE Paper 891842.

[10].L. G. Dodge, et al., 1998, “Development of an Ethanol-

Fueled Ultra-Low Emissions Vehicle”, SAE 981358.

[14]. K. Iwachidou, and M. Kawagoe, 1988, “Transient

Unburned Methanol and Formaldehyde Emission

Characteristics in Cold Operation of a SI Engine Powered

by High-Methanol-Content Fuels”, VIII Int. Symp. On Alcohol

Fuels, pp. 443-448.

[15].N. Iwai, et al., 1988, “A Study on Cold Start ability

and Mixture Formation of High-Percentage Methanol

Blends”, SAE Paper 880044.

[16]. D. M. Swain, and D. Yerace, 2002, “Cold-Start

Hydrocarbon Reduction Strategy for Hybrid Vehicles, M.

S. Thesis, University of Michigan.

[17]. W. Clemmens, 1987, “Performance of Sequential Port

Fuel Injection on a High Compression Ratio Neat

Methanol Engine”, SAE Paper 872070.

[18]. C. D. de Boer, et al., 1988, “The Optimum Methanol

Engine with Electronic Control for Fuel Efficiency and Low

Emissions”, VIII Int. Symp. On Alcohol Fuels, pp. 425-430.

[19]. R. I. Bruetsch, and K. H. Hellman, 1992, “Evaluation of

a Passenger Car Equipped with a Direct Injection Neat

Methanol Engine”, SAE Paper 920196.

[20] Priesching, P., Ramusch, G., Ruetz, J. and Tatschl, R.,

2007, “3D-CFD Modeling of conventional and Alternative

Diesel Combustion and Pollutant Formation - A Validation

Study”, SAE 2007-01-1907.


ANNEX A

EXPERIMENTAL DATA

Experimental Data compression ratio ( CR-17.5:1)

Experimental data ethanol of split injection mode without zirconia coating (pre and post injection) CR-28.8:1

Experimental Data ethanol split injection mode with zirconia coating (pre and post injection) compression Ratio -28.8:1


an experimental study of performance and emission on

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