Chandrasekar Presentation

8/2/2019 Chandrasekar Presentation

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Combustion, performance and

emission characteristics of a diesel

engine fueled with a pumpkin oilmethyl ester

P. CHANDRASEKAR

NIT ROURKELA

Guided by

Dr. S. Murugan


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Twin issues related to depletion of petroleum reserves,

increasing the vehicle population has forced to development

of alternative energy sources. The most suitable alternative

fuel is vegetable oil, because it is renewable in nature and

more environments friendly.

Much research has been done to use of vegetable oils as a

transport fuel. The direct use of vegetable oils in fuel

engines is not encouraged. Due to their high viscosity (11-17 times higher than diesel fuel) and low volatility, they do

not burn completely and form deposits in the fuel injector of

diesel engines.

Introduction


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There are four ways to use vegetable oil in a diesel engine:

(i) direct use or blending in diesel fuel, (ii) micro emulsions

in diesel fuel, (iii) thermal cracking (pyrolysis) of the

vegetable oil, and (iv) transesterification to producebiodiesel. Among these, the transesterification is the

commonly used commercial process to produce clean and

environmental friendly fuel.

The main cultivation of pumpkin seed areas are South andEast Austria and neighbouring countries, southern parts of

North America and Central America, some regions in Africa

as well as Asia.

Cont


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Experimental setup

DAS

LOADCELL

SMOKEMETER

GASANALYSER

ALTERNATOR

AIR TANK

ENGINE


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Make KirloskarModel TAF 1Bore x Stroke 87.5 x 110 mmCompression ratio 17.5:1Rated power 4.4 kWRated speed 1500 rpmStart of injection 23o bTDCNozzle opening pressure 200 bar

Engine specification


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PROPERTIES PSO POME DIESEL

Kinematic viscosity (40oC), mm2/sec 35.6 4.41 35Density (15

o

C), kg/m3 921.6

883.7

836

866

Flash point, oC >230 >120 4576Sulphur content, g/g 2 2 0.050.5Water content, g/g 584 490 Iodine number 115 115 Net calorific value MJ/kg 35.1 34.27 44.8

Physical and Chemical properties


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PUMPKIN OIL

MEHTYL ESTER


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Combustion parameters

Ignition delay

Pressure-crank angle

Heat release rate Performance parameters

Brake thermal efficiency

Exhaust gas temperature

Emission parameters NO emission

CO emission

Smoke density

Result and discussion


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Ignition delay with brake

power

10

11

12

13

14

15

0 1.1 2.2 3.3 4.4

IgnitiondelayinoCA

Brake power in kW

DIESEL POME10

POME20 POME30

POME40 POME50

POME


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Ignition delay is defined as the time difference in

crank angle between start of injection and start of

ignition. Ignition delay determines the premixed

combustion, heat release, maximum pressure and rateof pressure rise.

The shorter ignition delay of POME50 and POME is

due to higher cetane number of POME and its blendcompared to diesel.


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cylinder pressure with crank

angle

0

10

20

30

40

50

6070

80

90

330 360 390

Pressure,

bar

Crank angle , oCA

DIESEL

POME10

POME20

POME30

POME40

POME50

POME


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The cylinder pressure characterized by the ability of

the fuel to mix well with air and burn.

It is observed that the POME50 is higher than that ofdiesel. This may be due to the ignition delay period

increases with the decrease of engine load. At low

engine loads, because of the longer ignition delay

period, combustion starts later for diesel fuel than forbiodiesel blend.

For POME, the cylinder pressure is lower than diesel,

due to high viscosity and low volatility of biodiesel.


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Heat release rate with crank

angle

-10

0

10

20

30

40

50

60

70

330 360 390

HeatreleaserateJ/oCA

Crank angle in oCA

DIESEL

POME10

POME20

POME30

POME40

POME50

POME


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It can be observed that the heat release rate of POME

and its diesel blend is lower than that of diesel, this

may be due to POME and its blend attributes lower

calorific value than diesel fuel so it contributes lower

heat release.

At the time of ignition, less fuel/air mixture is

prepared for combustion with the diesel blend;therefore, more burning occurs in the diffusion-

burning phase rather than in the premixed phase.


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Brake thermal efficiency with

load

0

5

10

15

20

25

30

35

0 25 50 75 100

Braketherm

alefficiency,%

Load, %

DIESEL POME10

POME20 POME30

POME40 POME50

POME


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It can be observed that the brake thermal efficiency of

the tested fuels increase, with increase in the load.

The trends of the brake thermal efficiency of POME

and its blends are higher than that diesel, due to

presence of increased amount of oxygen in POME

and its blends, and additional lubricity.

The maximum brake thermal efficiency for POME atfull load is 33.05% for POME, which is 3.46% higher

than that of diesel.


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Exhaust gas temperature with

load

0

50

100

150

200

250300

350

0 25 50 75 100

Exhust

gastemperature,

oC

Load, %

DIESEL POME10

POME20 POME30POME40 POME50

POME


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For POME and its blends the exhaust gas temperature

is higher compared to that of diesel fuel.

This may be due to longer ignition after burning

stage. Longer ignition delay results in a delayed

combustion and higher exhaust temperature


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NO emission with load

0

50

100

150

200

250

0 25 50 75 100

NOemission,ppm

Load, %

DIESEL POME10

POME20 POME30

POME40 POME50

POME


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For all loads the NO emission for POME and its

blends is higher than that of diesel fuel, except 40%

blend is lower at full load.

The reason for higher NO emission for POME and itsblends is due to higher cylinder temperature.

Another reason may be due to oxygen content present

in biodiesel and its blends. The NO emissions level

was found to be directly related to the exhaust gastemperature while it was inversely related to the

smoke and CO values.


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CO emission with load

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0 25 50 75 100

CO

emission,

%vol

Load, %

DIESEL POME10

POME20 POME30POME40 POME50

POME


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From the figure, it can be observed that the CO

emissions are lower for POME and its blends as

compared to that of diesel fuel.

Lower CO emissions form biodiesel fuelled enginemay be due to their more complete oxidation

compared to that of diesel.

Some of the CO produced during combustion of

biodiesel might have converted into CO2by taking upthe extra oxygen molecule present in the biodiesel

chain and thus reduced CO formation


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Smoke density with blends

05

10

15

20

25

30

35

40

45

Smokedensity,%

No load 25% 50%

75% Full load


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It can be observed that the smoke density is lower for

POME and its blends than that of diesel fuel.

But, POME gives more smoke density than the diesel

blends that may be due to higher viscosity of POME. The main reason for lower smoke density for diesel

blends may be due to the complete and stable

combustion of the biodiesel and its blends, which

contains more number of oxygen atoms


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It is concluded that neat pumpkin biodiesel (POME)which results in shorter ignition delay andcombustion duration.

The values heat release rate, pressure crank angle and

rate of pressure rise are comparable with standarddiesel fuel.

The pumpkin oil methyl ester gives better efficiencyand lower emissions as compared to that of dieselfuel.

The analysis reveals that methyl ester from unrefinedpumpkin seed oil is quite suitable as an alternative fordiesel engine.

Conclusion


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Sinha S, Agarwal AK. Combustion characteristics of rice bran oil derived biodiesel in atransportation diesel engine. SAE Paper No. 2005-01-1730; 2005.

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References


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