effect of injection timing and injection pressure on a single cylinder diesel engine for better...

International Journal of Advances in Engineering & Technology, Mar. 2013.

©IJAET ISSN: 2231-1963

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

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 27obtdc 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 31obtdc. 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.



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

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.

Table – 1 Specification of the engine

Make 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. 48 – 56 23 / 51 57

Density(kg/m 3 ) 821 920 892

Viscosity (cSt) 3.52 75,7 5.402

Calorific value (MJ/kg) 43 39,628 39.15

Flash point (°C) 48 340 156



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

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



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

Fig 3 - BSFC VS BP AT 200 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/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.

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

BSFC VS Brake Power for 180 bar pressure 31O BTDC

0

0.2

0.4

0.6

0.8

0.92 1.83 2.75 3.675 Brake Power (Kw)

bsfc

(Kg/K

w-h

r)

hr)

DIESEL

CNG-DIESEL


0

0.2

0.4

0.6

0.8

1

0.92 1.83 2.75 3.675

Brake Power (Kw)

bsfc

(Kg/K

w-h

r)

DIESEL

CNG-DIESEL



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



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

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

BTE VS Brake Power for 180 bar pressure 27O BTDC

0

5

10

15

20

25

30

0.92 1.83 2.75 3.675 Brake Power (Kw)

BT

E(%

)

DIESEL

CNG-DIESEL


0

0.2

0.4

0.6

0.8

0.92 1.83 2.75 3.675 Brake Power (Kw)

bsfc

(Kg/K

w-h

r)

hr)

DIESEL

CNG-DIESEL


0

0.2

0.4

0.6

0.8

0.92 1.83 2.75 3.675 Brake Power (Kw)

bsfc

(Kg/K

w-h

r)

hr)

DIESEL

CNG-DIESEL



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



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



0

10

20

30

0.92 1.83 2.75 3.675

Brake Power (Kw)

BT

E(%

)

DIESEL

CNG-DIESEL

BTE Vs Brake Power for 200 bar pressure 27O BTDC

0

10

20

30

0.92 1.83 2.75 3.675 Brake Power (Kw)

BT

E(%

)

DIESEL

CNG-DIESEL

BTE VS Brake Power for 180 bar pressure 31 deg btdc

0

5

10

15

20

25

30

0.92 1.83 2.75 3.675

Brake Power(Kw)

BT

E(%

)

DIESEL

CNG-DIESEL



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


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.

BTE VS Brake Power for 220 bar 31O BTDC

0

10

20

30

40

0.92 1.83 2.75 3.675

Brake Power (Kw)

BT

E(%

)

DIESEL

CNG-DIESEL


0

10

20

30

40

0.92 1.83 2.75 3.675

Brake Power (Kw)

BT

E(%

) DIESEL

CNG-DIESEL



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

3.2. EMISSIONS

Un Burnt Hydro Carbons

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


UBHC VS Brake Power for 200 bar 31O BTDC

0

50

100

150

200

250

300

350

400

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL

UBHC VS Brake Power 180bar 31O BTDC

0

50

100

150

200

250

300

350

400

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL



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


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

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

CO VS Brake Power 180 bar 31O BTDC

0

0.05

0.1

0.15

0.2

0.25

0 0.92 1.83 2.75 3.68 Brake Power (Kw)

DIESEL CNG-DIESEL

UBHC VS Brake Power for 220 bar 31O BTDC

0

50

100

150

200

250

300

350

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL



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

Fig 18 - CO VS BP AT 200 BAR 31O BTDC

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.

CO VS Brake Power for 220bar 31O BTDC

0

0.05

0.1

0.15

0.2

0.25

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL

CO VS Brake Power for 200 bar 31O BTDC

0

0.05

0.1

0.15

0.2

0.25

0.3

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL



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

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



Figure 20, 21 and 22 shows variation of smoke density 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 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.

Smoke Density VS Brake Power for 220 bar 31O BTDC

0 10 20 30 40 50 60 70 80

0 0.92 1.83 2.75 3.68 Brake Power (Kw)

DIESEL CNG-DIESEL

Smoke Density VS Brake Power for 200bar 31O BTDC

0

20

40

60

80

100

120

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL CNG-DIESEL

Smoke Density VS Brake Power 180bar 31O BTDC

0 10 20 30 40 50 60 70 80

0 0.92 1.83 2.75 3.68 Brake Power (Kw)

DIESEL CNG-DIESEL



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

Fig 23 - Nox VS BP AT 180 BAR 31O BTDC



NOx VS Brake Power for 220bar 31O BTDC

0

20

40

60

80

100

120

140

160

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL

NOx vs Brake Power for 200 bar 31O BTDC

0

20

40

60

80

100

120

140

160

0 0.92 1.83 2.75 3.68

Brake Power (Kw)

DIESEL

CNG-DIESEL

NOx VS Brake Power 180 bar 31O BTDC

0 20 40 60 80 100 120 140 160 180

0 0.92 1.83 2.75 3.68 Brake Power (Kw)

DIESEL CNG-DIESEL



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

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

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[10]. Sahoo P.K. and L.M.Das “(2009) Combustion analysis of jatropha, Karanja and Polanga based

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P.No 251-255 Vol17 (4) Aug 2010.



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

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.

effect of injection timing and injection pressure on a single cylinder diesel engine for better...

Design

diesel oil

jatropa bio diesel

jatropa biodiesel

cng jome

stroke diesel engine

single cylinder diesel

vegetable oil derived

jome single