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International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963

EFFECT OF INJECTION TIMING AND INJECTION PRESSURE
ON A SINGLE CYLINDER DIESEL ENGINE FOR BETTER
PERFORMANCE AND EMISSION CHARACTERISTICS FOR
JATROPA BIO DIESEL IN SINGLE AND DUAL FUEL MODE
WITH CNG
Meyyappan Venkatesan
Assistant Professor, Mechanical Engineering,
Ethiopian Institute of Technology [EIT – M], Mekelle University, Ethiopia

ABSTRACT
In the present investigation test were carried out to examine the performance and emissions of a direct injection
diesel engine blended with Jatropa bio-diesel prepared with methanol to get jatropa oil methyl ester (JOME) .
Experiments are conducted with JOME single and dual fuel mode with compressed natural gas (CNG) in a
single cylinder 4 stroke diesel engine. Performance parameters such as brake thermal efficiency (BTE) and
brake specific fuel consumption (BSFC), emissions such as CO, UBHC, smoke density and NOx are determined
at three injection pressures of 180, 200 and 220 bar and two injection timings 27 obtdc and 31obtdc. Parameters
are compared with base line data of diesel fuel. It was found through experiments that CNG - JOME can be
used as fuel with better performance at 220 bar pressure and advanced injection timing of 31 obtdc. The harmful
pollutants such as UBHC, CO and NOx are reduced in jatropa oil methyl ester with CNG in single and dual fuel
mode compared to diesel fuel.

KEYWORDS: Jatropa oil methyl ester - performance – emission characteristics - dual fuel mode – CNG.

I.

INTRODUCTION

Motor vehicles contribute significantly to the air pollutions problems. Therefore use of alternative
fuels can help in the promotion of environmental protection. Increased consumption of conventional
based fuel gives way for the exploration of several alternative fuels. Important requirement of
automotive fuels such as high energy density safety in usage and handling, conveniences in
transportation, storage and cost but not the least environmental acceptability make bio-diesel
especially jatropa oil a vegetable oil derived fuel and among the gaseous fuels Compressed natural
Gas as the strongest contenders to replace the petroleum derived fuels.
Major problems associated with direct use of vegetable oils are their viscosity, volatility and heating
value. Excessive carbon deposits and thickening of lubricating oil are the problems associated with
direct use of straight vegetable oils. Properties can be improved by preparing esters of jatropa with
methanol to form jatropa oil methyl ester (JOME).
Among the various alternative fuels bio-diesel is one of the most promising liquid fuels for CI
engines. Gaseous fuels such as compressed natural gas (CNG), biogas, hydrogen, liquefied petroleum
gas have been tried. Gaseous fuels are promising because they are less polluting for environment.
They form premixture very easily. Taking into consideration the availability and development in India
regarding bio-diesel and CNG the present work has concentrated on utilization of JOME bio-diesel
and CNG as alternative fuel in CI engine.

21

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
Notations used:
BSFC: Brake specific fuel consumption
BTE: Brake thermal efficiency
BSEC: Brake specific energy consumption
UBHC: Un burnt hydrocarbon
CO: Carbon monoxide
NOx: Nitric oxides

II.

PROCEDURE

Engine Test
Engine running tests were conducted on Kirloskar make, single cylinder,4-stroke-cycle, constant
speed (1500 rpm) vertical, water cooled, direct injection, 5hp (3.7 kW), bore 100 mm and stroke
110mm, compression ratio 20:1 diesel engine. Tests were conducted at different loads, with diesel oil,
transesterified oil (JOME) CNG-Diesel and CNG-JOME for comparative study. The experimental
setup of the engine is shown in figure 1a. An eddy current dynamometer was used for load
measurement. The engine speed was sensed and indicated by an inductive pick up sensor facing
marks on flywheel with digital meter output. Chromel-alumel thermocouple was used for exhaust gas
temperature measurement. Figure 1b shows AVL make smoke meter used for smoke measurement.
Carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC), nitrous oxide (NOx) were
measured by MRU air emission monitoring systems shown in figure 1c.Fuel consumption is measured
by a burette with two sensors placed apart two markings to measure 20cc accurately.
Make

Table – 1 Specification of the engine
Kirloskar, single cylinder

Type

direct injection, water cooled

Bore X Stroke (mm)

100 X 110

Compression ratio

20:1

Rated power

5hp (3.7 kW),

Rates speed

constant speed (1500 rpm)

Start of injection

180 bar

Table – 2 Range of operating parameter tried in the present testing
% Load

20% 40% 60% 80% and 100%

Speed

constant speed (1500 rpm)

Compression ratio

20:1

Injection Timing obTDC

27 o bTDC and 31 o bTDC

Injection Pressure

180bar, 200bar and 220 bar

Table.3 Properties of Biodiesel compared with neat diesel
Properties
Diesel
Jatropha
BioDiesel (Methyl
Ester)
Cetane No.
Density(kg/m 3 )
Viscosity (cSt)
Calorific value (MJ/kg)
Flash point (°C)

22

48 – 56
821
3.52
43
48

23 / 51
920
75,7
39,628
340

57
892
5.402
39.15
156

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963

a. Engine Set up

b. Smoke meter

c. Exhaust Gas analyzer
Figure 1- Equipment used in Conducting Tests

2.1 Test Procedure
Engine tests were conducted at 27° btdc and 310 btdc injection timings and injection pressures of
180bar, 200bar and 220 bar respectively. Engine was started on neat diesel and warmed up till cooling
water temperature was stabilized. Fuel consumption, exhaust temperature, exhaust emissions such as
UBHC, NOX, CO2, CO and exhaust gas opacity were measured and recorded for different loads.
Similar procedure was repeated for CNG-diesel for constant flow rate of CNG of 0.4kg per hour at
constant speed of 1500rpm.Since a governor is used in the engine to regulate the flow rate of diesel to
keep the engine speed constant, natural gas flow rate is maintained constant. Tests were repeated for
20%, 40%, 60%and 80% loading conditions. Three readings were taken for each load and average
value is used for calculations.

III.

RESULTS AND DISCUSSIONS

3.1 Engine performance
Brake Specific fuel consumption (BSFC)

Fig 2 – BSFC VS BP AT 180 BAR 27O BTDC

23

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963

Fig 3 - BSFC VS BP AT 200 BAR 27O BTDC

bsfc(Kg/Kw-hr)

BSFC VS Brake Power for 220 bar pressure 27O BTDC

1
0.8
0.6
0.4
0.2
0

DIESEL
CNG-DIESEL

0.92

1.83

2.75 3.675

Brake Power (Kw)

Fig 4 - BSFC VS BP AT 220 BAR 27O BTDC

Figure 2, 3 and 4 shows variation of brake specific fuel consumption with brake power curves for
diesel and CNG-Diesel operation of the engine at 27 deg btdc and 180bar, 200bar and 220bar
injection pressures respectively. BSFC of diesel at standard injection pressure of 180 bar and injection
timing of 27 deg btdc is 0.61Kg/Kw-hr at low loads of operation. At higher loads of operation BSFC
is 0.30Kg/Kw-hr. The values for CNG-Diesel for low load and higher loads are 0.83 and 0.32Kg/Kwhr For CNG-Diesel at all the three injection pressures at low loads it is 0.83Kg/Kw-hr with very little
variations and it is nearly equal to that of diesel at higher loads. This is because of better mixing and
atomization of fuel at higher injection pressures.
BSFC VS Brake Power for 180 bar pressure 31O BTDC

0.6

DIESEL

0.4
0.2
0

CNG-DIESEL

hr)

bsfc(Kg/Kw-hr)

0.8

0.92

1.83

2.75 3.675

Brake Power (Kw)

Fig 5 - BSFC VS BP AT 180 BAR 31O BTD

24

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
BSFC VS Brake Power for 200 bar pressure 31O BTDC

bsfc(Kg/Kw-hr)

0.8
0.6

DIESEL

0.4
hr)

CNG-DIESEL

0.2
0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 6 - BSFC VS BP AT 200 BAR 31O BTDC

BSFC VS Brake Power for 220 bar pressure 31O BTDC

0.6

DIESEL

0.4

CNG-DIESEL

hr)

bsfc(Kg/Kw-hr)

0.8

0.2
0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 7 - BSFC VS BP AT 220 BAR 31O BTDC

Figure 5,6 and 7 shows variation of brake specific fuel consumption with brake power curves for
diesel and CNG-Diesel operation of the engine at 31 deg btdc and 180bar,200bar and 220bar injection
pressures respectively For CNG-Diesel operation at low loads of operation for all injection pressures
is 10%. At higher loads it is 27.8%, 27.75% and 28.74% at 180bar, 200bar and 220bar pressures
respectively. An increase of 1%in efficiency at higher pressures of 200bar and 220bar.Advancing the
injection timing improves the BTE due to longer time available for proper mixing and combustion

BTE(%)

BTE VS Brake Power for 180 bar pressure 27O BTDC

30
25
20
15
10
5
0

DIESEL
CNG-DIESEL

0.92

1.83

2.75 3.675

Brake Power (Kw)

Fig 8 - BTE VS BP AT 180 BAR 27O BTDC

25

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
BTE Vs Brake Power for 200 bar pressure 27O BTDC

BTE(%)

30
20

DIESEL
CNG-DIESEL

10
0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 9 - BTE VS BP AT 200 BAR 27O BTDC
BTE VS Brake Power for 220 bar pressure 27O BTDC

BTE(%)

30
20

DIESEL

10

CNG-DIESEL

0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 10 - BTE VS BP AT 220 BAR 27O BTDC

Figure 8, 9 and 10 shows variation of brake thermal efficiency with brake power curves for diesel and
CNG-Diesel operation of the engine at 27 deg btdc and 180bar,200bar and 220bar injection pressures
respectively BTE for diesel baseline at 180bar pressure 27 deg btdc is 13.75% and 28% t low and high
loads of operation respectively. For CNG-Diesel it is almost equal to 10% at all injection pressures
and at high loads it is 25.93%, 2.28% and 26.92% respectively at 180bar 200bar and 220bar pressures.
At higher pressures efficiency approaches to that of diesel due to better mixing and combustion of
fuel

BTE(%)

BTE VS Brake Pow er for 180 bar pressure 31 deg btdc
30
25
20
15
10
5
0

DIESEL
CNG-DIESEL

0.92

1.83

2.75

3.675

Brake Pow er(Kw )

Fig 11 - BTE VS BP AT 180 BAR 31O BTDC

26

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
BTE VS Brake Power for 200 bar pressure 31O BTDC

40
BTE(%)

30
DIESEL

20

CNG-DIESEL

10
0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 12 - BTE VS BP AT 200 BAR 31O BTDC

BTE VS Brake Power for 220 bar 31O BTDC

BTE(%)

40
30
DIESEL

20

CNG-DIESEL

10
0
0.92

1.83

2.75

3.675

Brake Power (Kw)

Fig 13- BTE VS BP AT 220 BAR 31O BTDC

Figure 11, 12 and 13 shows variation of brake thermal efficiency with brake power curves for diesel
and CNG-Diesel operation of the engine at 31 deg btdc and 180bar, 200bar and 220bar injection
pressures respectively. BSFC of CNG-Diesel at 180 bar pressure and 31 deg btdc is 0.70Kg/Kw-hr at
low loads of operation and at higher loads it is 0.25 Kg/Kw-hr.At higher loads of operation for 200bar
and 220 bar pressures it is 0.24 Kg/Kw-hr and 0.26 Kg/Kw-hr respectively. A very low bsfc of 0.24
Kg/Kw-hr is achieved at 200 bar pressure and 31 deg btdc. Advancing the injection timing improves
the bsfc due to better mixing and combustion process.

27

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
3.2. EMISSIONS
Un Burnt Hydro Carbons
UBHC VS Brake Power 180bar 31O BTDC

400
350
300
250
DIESEL

200

CNG-DIESEL

150
100
50
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 14 - UBHC VS BP AT 180 BAR 31O BTDC

UBHC VS Brake Power for 200 bar 31O BTDC
400
350
300
250
200
150

DIESEL

100

CNG-DIESEL

50
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 15 - UBHC VS BP AT 200 BAR 31O BTDC

28

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
UBHC VS Brake Power for 220 bar 31O BTDC

350
300
250
200

DIESEL

150

CNG-DIESEL

100
50
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 16 - UBHC VS BP AT 220 BAR 31O BTDC

Figure 14, 15 and 16 shows variation of unburnt hydrocarbons with brake power curves for diesel
and CNG-diesel operation of the engine at 31 deg btdc and 180bar,200bar and 220bar injection
pressures respectively. A very high value of nearly 320ppm is obtained at all pressures at low loads
for CNG-diesel operation when compared to very low value of 7ppm for diesel operation indicating
incomplete combustion due to improper mixing of liquid and gaseous fuels. It is nearly 65 ppm at
higher loads of operation at all the three pressures due to better mixing and combustion
CO VS Brake Power 180 bar 31O BTDC
0.25
0.2
0.15

DIESEL
CNG-DIESEL

0.1
0.05
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 17 - CO VS BP AT 180 BAR 31O BTDC

29

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
CO VS Brake Power for 200 bar 31O BTDC

0.3
0.25
0.2
DIESEL

0.15

CNG-DIESEL

0.1
0.05
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 18 - CO VS BP AT 200 BAR 31O BTDC
CO VS Brake Power for 220bar 31O BTDC

0.25
0.2
0.15

DIESEL
CNG-DIESEL

0.1
0.05
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)
Fig19 - CO VS BP AT 220 BAR 31O BTDC

Figure 17, 18 and 19 shows variation of carbon monoxide with brake power curves for diesel and
CNG-Diesel operation of the engine at 31 deg btdc and 180bar, 200bar and 220bar injection pressures
respectively. The values are nearly 0.15% atlow loads of operation at all the three pressures and 0.22
at higher loads. The values for diesel are 0.01 at low loads and 0.07 at higher loads of operation.

30

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
Smoke Density VS Brake Power 180bar 31O BTDC
80
70
60
50

DIESEL

40

CNG-DIESEL

30
20
10
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 20 - SMOKE DENSITY VS BP AT 180 BAR 31O BTDC

Smoke Density VS Brake Power for 200bar 31O BTDC

120
100
80

DIESEL

60

CNG-DIESEL

40
20
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 21 - SMOKE DENSITY VS BP AT 200 BAR 31O BTDC
Smoke Density VS Brake Power for 220 bar 31O BTDC

80
70
60
50
40
30

DIESEL
CNG-DIESEL

20
10
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 22 - SMOKE DENSITY VS BP AT 220 BAR 31O BTDC

Figure 20, 21 and 22 shows variation of smoke density with brake power curves for diesel and CNGDiesel operation of the engine at 31 deg btdc and 180bar,200bar and 220bar injection pressures
respectively. The values 2 to 30ppm at low loads and 55 to 97 at higher load at three pressures when
compared to 1to 71 for diesel from low load to high loads indicating higher temperatures of running
with CNG-diesel.

31

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
NOx VS Brake Power 180 bar 31O BTDC
180
160
140
120
100
80

DIESEL
CNG-DIESEL

60
40
20
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)

Fig 23 - Nox VS BP AT 180 BAR 31O BTDC
NOx vs Brake Power for 200 bar 31O BTDC

160
140
120
100

DIESEL

80

CNG-DIESEL

60
40
20
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)
Fig 24 - Nox VS BP AT 200 BAR 31O BTDC
NOx VS Brake Power for 220bar 31O BTDC

160
140
120
100

DIESEL

80

CNG-DIESEL

60
40
20
0
0

0.92

1.83

2.75

3.68

Brake Power (Kw)
Fig 25 - Nox VS BP AT 220 BAR 31O BTDC

32

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963
Figure 23, 24 and 25 shows variation of oxides of nitrogen with brake power curves for diesel and
CNG-Diesel operation of the engine at 31 deg btdc and 180bar,200bar and 220bar injection pressures
respectively. At low loads it approaches to that of diesel with 22ppm and at higher loads it is 140ppm
at all loads of operation due to higher temperatures of operation.

IV.

CONCLUSION

In this investigation the diesel engine have been set to run at compression ratio 20:1, advanced
injection timing 31°bTDC and injector pressure 220bar to arrive at the optimum for jatropa oil methyl
esters (JOME). In CNG-JOME dual fuel operation of the engine at 31 deg btdc, BSFC of 0.87
Kg/Kw-hr, 0.74 Kg/Kw-hr and 0.76 Kg/Kw-hr were obtained at low loads of operation at 180bar,
200bar and 220bar pressures. At higher loads the values are 0.29Kg/Kw-hr,0.26Kg/Kw-hr and
0.27Kg/Kw-hr for 180bar, 200bar and 220bar injection pressures respectively. BSFC at higher loads
is even less than diesel operation at all pressures with advanced injection timings due to slow flame
velocities and clean burning.
The values for CNG-Diesel (single fuel) for low load and higher loads are 0.83 and 0.32Kg/Kw-hr
For CNG-Diesel at all the three injection pressures at low loads it is 0.83Kg/Kw-hr with very little
variations and it is nearly equal to that of diesel at higher loads. This is because of better mixing and
atomization of fuel at higher injection pressures. An increase in Brake thermal efficiency of 1.28% is
obtained at higher loads when compared to base line diesel operation due to the advancement in
injection timing. At low loads the UBHC is high and it reduces at high load conditions. Pressure
variation does not have any effect on NOx and CO emissions but higher pressure causes higher value
of smoke density.
Finally it can be concluded that CNG - JOME dual fuel mode could be used as alternative fuel for
operating CI engine at compression ratio of 20:1, higher injector operating pressure of 220 bar and
advanced injection timing of 31ºbTDC for optimum engine performance and lower emissions.

REFERENCES
[1]. Agarawal.A.K. & Das.L.M. “Biodiesel development and characterization for use as a fuel in
compression ignition engines”, pp. 440-447, Transactions of ASME, Vol.123, April 2001.
[2]. Avinash kumar Agarwal and Deepak Agarwal (2007) “Performance and emission characteristics of
Jatropha oil (preheated and blends) in a direct injection compression ignition engine”Elsevier –Applied
Thermal Engineering 2314-2323.
[3]. G.H. Abd Alla, H.A. Soliman, O.A. Badr, M.F. Abd Rabbo,“effect of pilot fuel quantity on the
performance of a dual fuel engine” pp269-277,Energy Conversion and Management, Vol 43, 2002.
[4]. Karim G.A.(1983) “The dual fuel engine of compression ignition type –prospects, problems and
solutions –A review” SAE Paper NO 831073, P3569.
[5]. Karim G.A. An Examination of some Measures for Improving the Performance Gas fuelled diesel
engines at light load SAE Paper No912366,1991, p966.
[6]. Lakshminarayanarao G. and K.Rajagopal(2007) “Combustion Analysis of Diesel engine Fueled with
jatropha oil methyl esters – Diesel blends ”Int Journal of Green Energy 2007.
[7]. Liu.Z and Karim.G.A. ”The Ignition delay period in dual fuel engines.”SAE Paper No 950466, 1995,
p356.
[8]. Nwafor O.M.I “ Effect of Advanced Injection Timing on the performance of natural gas in Diesel
Engine” Sadhana,Vol 25,part 1,2000,p11..Nwafor O.M.I,” Emission characteristics of Diesel engine
operating on Rapeseed methyl ester”,Rewnewable Energy,vol.29,pp.119-129,2004.
[9]. Papagiannakis R.G. and Houtalas D.T. “Combustion and exhaust emission characteristics of dual fuel
compression ignition engine operated with pilot diesel fuel and natural gas.” Energy and management
45, 2004, P2971
[10]. Sahoo P.K. and L.M.Das “(2009) Combustion analysis of jatropha, Karanja and Polanga based
biodiesel as fuel in a diesel engine”Elsevier-Fuel 994-999.
[11]. Experimental investigation of performance and emission characteristics of oxygenated compounds in a
DI diesel engine using split injection method “Indian Journal of Engineering and Material Science
P.No 251-255 Vol17 (4) Aug 2010.

33

Vol. 6, Issue 1, pp. 21-34

International Journal of Advances in Engineering & Technology, Mar. 2013.
©IJAET
ISSN: 2231-1963

AUTHOR PROFILE:
M. Venkatesan received the Ph. D Award from the International University of
Contemporary Studies, Washington DC in 2009, Masters in Thermal Engineering
(2001) and Bachelor Degree in Mechanical Engineering (1997) from University of
Madras. He is currently working as Assistant Professor in Mekelle University –
Ethiopia and he has also served as Vice Principal (Academics) in PMR Engineering
College, Chennai, TamilNadu, India. He has more than 14+ years of experience in
Teaching, Research and Administration at National and International Levels. His fields
of interests are various, viz., Alternative fuels, Heat Transfer, Aeronautics, Design, and
Supply chain Management. He has more than 10 publications to his credit both in
National and International Journals and conferences and has authored 5 books on
Engineering viz., Engineering Mechanics, Aero Engineering Thermodynamics, Fluid
Mechanics and Fluid Machinery, Engineering Graphics and Workshop Practice as per
Anna University Chennai regulation. He has dedicated his whole soul and life to
research and education and he has been serving as Editorial Board Member, Advisory
Board Member and Editor-in-Chief for International Journals.

34

Vol. 6, Issue 1, pp. 21-34


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