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Idris2009-Thesis-CNG-4StrokeIgnitionEngine.pdf
EFFECT OF COMPRESSED NATURAL GAS ON PERFORMANCE AND
EMISSION OF A 4-STROKE SPARK IGNITION ENGINE
AWANG BIN IDRIS
Thesis submitted in fulfilment of the requirements
for the award of the degree of
Master of Engineering (Automotive)
Faculty of Mechanical Engineering
UNIVERSITI MALAYSIA PAHANG
NOVEMBER 2009
v
ABSTRACT
This thesis deals with experimental study of a four-stroke spark ignition engine. The
objective of this thesis is to evaluate the performance and emission characteristics of the
engine while using conventional fuel, gasoline and alternative fuel, compressed natural
gas (CNG). The engine operated under a steady state condition at wide-open throttle
condition. The performance and emissions test was performed with various constant
loads at different speed within the range of 1500 rpm to 4000 rpm with 500 rpm
interval. The first experiment is executed by using gasoline and followed by CNG. The
engine performance and emissions such as air-fuel ratio, torque, brake power, brake
specific fuel consumption, efficiency, the concentration of CO, CO2, HC, and NOx of
gasoline and CNG were measured. The results demonstrated that the potential of
reducing emissions while applying CNG as fuel is obvious. However the performance of
CNG is reduced as the brake power of engine decrease around 25% compare to gasoline
engine. During operate with CNG the engine emissions of CO, CO2 and HC shows a
significant reduction but the NOx emission is highly increased compare to gasoline. The
results and analysis will be useful for the development of dedicated gas engine in the
near future.
vi
ABSTRAK
Tesis ini membentangkan keputusan ujikaji enjin nyalaan bunga api bagi menilai
prestasi dan ciri-ciri emisi apabila menggunakan bahan api gasolin dan gas asli
termampat (CNG). Bagi menilai prestasi engine, operasi dilakukan dengan kelajuan
enjin antara 1500 ppm hingga 4000 ppm, di bawah keadaan mantap dengan pendikit
terbuka luas (wide-open throttle). Ujian emisi dijalankan dengan menggunakan beban
tetap yang berbeza pada setiap kelajuan. Prestasi dan keluaran engin seperti nisbah
udara-bahan api, daya kilas, kuasa brek, penggunaan bahan api tentu brek CO, CO2, HC
dan NOx dari CNG diukur dan dibandingkan dengan bahan api gasolin. Keputusan
kajian menunjukkan CNG sangat berupaya mengurangkan keluaran berbanding dengan
gasolin. Walau bagaimana pun, prestasi CNG berkurangan, di mana kuasa brek
menurun sehinga 25% pada berbanding dengan gasolin. Semasa beroperasi dengan
CNG keluaran engine seperti CO, CO2 dan HC sangat berkurangan tetapi keluaran NOx
meningkat dengan begitu tinggi berbanding dengan gasolin. Keputusan dan analisa yang
dibuat sangat berguna untuk kajian lanjut bagi tujuan pembangunan enjin gas pada masa
depan.
vii
TABLE OF CONTENTS
Page
SUPERVISOR’S DECLARATION
ii
STUDENT’S DECLARATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xii
LIST OF SYMBOLS
xiv
LIST OF ABBREVIATIONS
xvi
CHAPTER 1
INTRODUCTION
1.1
Introduction
1
1.2
Malaysian Scenario
2
1.3
Problem Statement
4
1.4
Objectives of the Research
5
1.5
Scope of the Project
1.6
Thesis Organization
CHAPTER 2
LITERATURE REVIEW
2.1
Introduction
6
2.2
World Fuel Supplies
6
2.3
CNG as Alternative Fuel
7
2.4
Characteristics of CNG
9
viii
2.5
2.4
Research on CNG Vehicle
11
2.5.1 Engine Performance
17
2.5.2 Emissions
20
2.5.3 Emissions of Engine
24
Summary
34
CHAPTER 3
METHODOLOGY
3.1
Introduction
28
3.2
Overall Research Methodology
28
3.3
Experimental Apparatus
29
3.4
Description of Apparatus
32
3.4.1 Combustion Analysis
34
3.4.2 Exhaust Gas Analysis
36
3.5
Experimental Procedure
38
3.6
Performance Parameter
41
3.6.1
Brake Power
41
3.6.2
Mean Effective Pressure
42
3.6.3
Air-Fuel Ratio
43
3.6.4
Specific Fuel Consumption
44
3.6.5
Efficiency
44
3.6
Summary
CHAPTER 4
46
RESULTS AND DISCUSSION
4.1
Introduction
47
4.2
Cylinder Pressure
47
4.3
Engine Performance
50
4.3.1
Air-Fuel Ratio
50
4.3.2
Torque
51
4.3.3
Power
53
ix
4.4
4.3.4
Fuel Consumption
56
4.3.5
Brake Mean Effective Pressure
59
4.3.6
Efficiency
60
4.3.7
Emissions of the Engine
Summary
CHAPTER 5
72
CONCLUSION AND RECOMMENDATIONS
5.1
Introduction
73
5.2
Conclusions
73
5.3
Recommendations for the Future Research
74
REFERENCES
75
APPENDICES
79
A
Dynamometer Load Cell Calibration
81
B
The Estimated of Maximum Gas Flowrate of Gas Flowmeter
81
C
Manual of TN SIC CNG Regulators
83
D
Calibration of Thermocouples
88
E
List of Publications
98
x
LIST OF TABLES
Table No.
Title
Page
1.1
The history of natural gas application for vehicle in Malaysia
2
2.1
Criteria affecting the suitability of alternative fuel
8
2.2
Dennis dart fuel requirement for various alternative fuel
8
3.1
Proton Magma 4G15 engine specification
32
4.1
Measured maximum peak pressure of gasoline and CNG at TDC
49
4.2
CNG torque reduction compare to gasoline
52
4.3
CNG brake power reduction compare to gasoline
55
4.4
CNG fuel flow rate reduction compare to gasoline
56
4.5
BSFC reduction of CNG compare to gasoline
58
4.6
BMEP reduction of CNG compare to gasoline
59
4.7
Brake thermal efficiency of CNG compare to gasoline
61
4.8
Typical value of mechanical efficiency of naturally aspirated SI
62
engine
xi
4.9
Typical value of volumetric efficiency of naturally aspirated SI
64
engine
4.10
CO concentration reduction of CNG compare to gasoline
66
4.11
CO2 concentration reduction of CNG compare to gasoline
67
4.12
HC concentration reduction of CNG compare to gasoline
69
4.13
Increment of NOx concentration reduction of CNG compare to
71
gasoline
xii
LIST OF FIGURES
Figure No.
Title
Page
2.4
Energy distributions
18
3.1
Flowchart of the studies
29
3.2
Schematic diagram of the engine test-bed
30
3.3
Figure of original test-rig
31
3.4
Dewetron CA combustion analyzer
35
3.5
Installed pressure sensor spark-plug
35
3.6
Bolted crank angle encoder
36
3.7
Crank angle encoder and data acquisition kit
36
3.8
Pressure sensor spark-plug
37
3.9
KEG-500 exhaust gas analyzer
38
4.1
Cylinder pressure distribution against CA degree of gasoline for
48
wide-open throttle condition
4.2
Cylinder pressure distribution against CA degree of CNG for
48
xiii
wide-open throttle condition
4.3
Air-fuel ratio at different engine speed for wide-open throttle
51
4.4
Torque at different engine speed for wide-open throttle
52
4.5
Indicated power at different engine speed for wide-open throttle
54
4.6
Brake power at different engine speed for wide-open throttle
55
4.7
Fuel flow rate at different engine speed for wide-open throttle
57
4.8
BSFC at different engine speed for wide-open throttle
58
4.9
BMEP at different engine speed for wide-open throttle
60
4.10
Brake thermal efficiency at different engine speed for wide-open
61
throttle
4.11
Mechanical efficiency at different engine speed for wide-open
63
throttle
4.12
Volumetric efficiency at different engine speed for wide-open
64
throttle
4.13
CO cocentration at different engine speed for wide-open throttle
66
4.14
CO2 concentration different engine speed for wide-open throttle
68
4.15
HC concentrayion at different engine speed for wide-open throttle
70
4.16
NOx concentraionat different engine speed for wide-open throttle
72
xiv
LIST OF SYMBOLS
B
Bore
CF
Correction factor
Cd
Coefficient of drag
L
Stroke
ma
Air flow rate

Fuel flow rate

Air flow rate
mf
ma
P
Pressure diffrent
Pi,m
Measured indicated power
Ps, d
Standard dry-air absolute pressure
Pm
Measured ambient-air absolute pressure
Pi, s
Standard indicated power
Pb
Brake power
Pf
Measured friction power
Pi, g
Indicated gross power
Pb, m
Measured Brake power
Patm
Atmosphere pressure
Pi
Measured indicated power
QLHV
Low heating value
xv
_
Sp
Mean piston speed
Ts
Standard ambient temperature
Tamb
Temperature during experiment
Vd
Displaced volume
 air
Air density
tf
Time of fuel consumption in second
ηbth
brake thermal efficiency
 bth
Mechanical efficiency
v
Volumetric efficiency
xvi
LIST OF ABBREVIATIONS
AFR
Air-fuel ratio
BMEP
brake mean effective pressure
BSFC
Brake specific fuel consumption
BDC
Botton dead centre
CNG
Compressed natural gas
CO
Carbon monoxide
CO2
Carbon dioxide
DOHC
Double over-head cam
EGR
Exhaust gas recirculation
FMEP
Friction mean effective pressure
HC
Hydrocarbom
LPG
Liquified Petroleum Gas
PMEP
Pump mean effective pressure
SULEV
Super ultra low emissions vehicle
sfc
Specific fuel consumption
SI
Spark ignition
TDC
Top dead centre
TWC
Three-way catalytic converter
ULEV
Ultra low emission vehicle
WOT
Wide-open throttle
SUPERVISOR’S DECLARATION
We hereby declare that we have checked this thesis and in our opinion, this thesis is
adequate in terms of scope and quality for the award of the degree of Master of
Engineering (Automotive).
Signature
Name of Supervisor : DR. ROSLI ABU BAKAR
Position
: PROFESSOR
Date
: 14 NOVEMBER 2009
Signature
Name of Co-supervisor: DR. AHMAD SYAHRIZAN SULAIMAN
Position
: LECTURER
Date
: 14 NOVEMBER 2009
ii
STUDENT’S DECLARATION
I hereby declare that the work in this thesis is my own except for quotations and
summaries which have been duly acknowledged. The thesis has not been accepted for
any degree and is not concurrently submitted for award of other degrees.
Signature
Name
: AWANG BIN IDRIS
ID Number
: MMA05001
Date:
: 14 NOVEMBER 2009
iii
Dedicated to my beloved family and friends
iv
ACKNOWLEDGEMENTS
In the name of Allah, the Most Benevolent, the most Merciful. I wish to record
immeasurable gratitude and thankfulfulness to the One and The Almightly Creator, the
Lord and Sustainer of the universe, and mankind in particular. It is only through His
mercy and help that this work could be completed and it is ardently desired that this
little effort be accepted by Him to be of some service to the cause of humanity.
I am grateful and would like to express my sincere gratitude to my supervisors
Professor Dr. Rosli Abu Bakar and Dr. Ahmad Syahrizan for their germinal ideas,
invaluable guidance, continuous encouragement and constant support in making this
research possible. I also sincerely thank them for the time spent proofreading and
correcting my many mistakes. I really appreciate the consistent support from the first
day I applied to this graduate program to these concluding moments. I am truly grateful
for their progressive vision about my training in science, their tolerance of my naive
mistakes, and his commitment to my future career. I also would like to express very
special thanks to my internal and external examiner, Associate Professor Dr. Md
Mustafizur Rahman and Professor Dr. Ahmad Kamal Ariffin Mohd Ihsan for their
suggestions and co-operation througout the study
I would like to express my special thanks to Mr. Mohd Fadzil Abdul Rahim, Mr.
Nik Mohd Izual Nik Ibrahim, Mr. Ismail Ali, Mr. Semin Professor Dato’ Dr. Abu Azam
Md Yassin for supporting me since our first meeting in 1986 at UTM and all my
colleagues especially Mr. Shuib Husin, Mr. Mohd Rizal Abdul Latif, Mr. Saharul Arof
and Mr. The Sharifuddin Abdullah..
My sincere thanks go to all my labmates and members of the staff of the
Mechanical Engineering Department, UMP, who helped me in many ways and made my
stay at UMP pleasant and unforgettable. Many special thanks go to fellow engine
research group members for their excellent co-operation, inspiration and support during
this study. I would like also to express my special thanks to UniKL MSI and MARA for
support and sponsorship of my full-time study.
I acknowledge my sincere indebtedness and gratitude to my parents for their
love, dream and sacrifice throughout my life. I acknowledge the sincerity of my parentsin-law, who consistently encouraged me to carry on my higher studies in Malaysia. I am
also grateful to my wife Noor Hayati Seman, daughter and son for their sacrifice,
patience, and understanding that were inevitable to make this work possible.
v
ABSTRACT
This thesis deals with experimental study of a four-stroke spark ignition engine. The
objective of this thesis is to evaluate the performance and emission characteristics of the
engine while using conventional fuel, gasoline and alternative fuel, compressed natural
gas (CNG). The engine operated under a steady state condition at wide-open throttle
condition. The performance and emissions test was performed with various constant
loads at different speed within the range of 1500 rpm to 4000 rpm with 500 rpm
interval. The first experiment is executed by using gasoline and followed by CNG. The
engine performance and emissions such as air-fuel ratio, torque, brake power, brake
specific fuel consumption, efficiency, the concentration of CO, CO2, HC, and NOx of
gasoline and CNG were measured. The results demonstrated that the potential of
reducing emissions while applying CNG as fuel is obvious. However the performance of
CNG is reduced as the brake power of engine decrease around 25% compare to gasoline
engine. During operate with CNG the engine emissions of CO, CO2 and HC shows a
significant reduction but the NOx emission is highly increased compare to gasoline. The
results and analysis will be useful for the development of dedicated gas engine in the
near future.
vi
ABSTRAK
Tesis ini membentangkan keputusan ujikaji enjin nyalaan bunga api bagi menilai
prestasi dan ciri-ciri emisi apabila menggunakan bahan api gasolin dan gas asli
termampat (CNG). Bagi menilai prestasi engine, operasi dilakukan dengan kelajuan
enjin antara 1500 ppm hingga 4000 ppm, di bawah keadaan mantap dengan pendikit
terbuka luas (wide-open throttle). Ujian emisi dijalankan dengan menggunakan beban
tetap yang berbeza pada setiap kelajuan. Prestasi dan keluaran engin seperti nisbah
udara-bahan api, daya kilas, kuasa brek, penggunaan bahan api tentu brek CO, CO2, HC
dan NOx dari CNG diukur dan dibandingkan dengan bahan api gasolin. Keputusan
kajian menunjukkan CNG sangat berupaya mengurangkan keluaran berbanding dengan
gasolin. Walau bagaimana pun, prestasi CNG berkurangan, di mana kuasa brek
menurun sehinga 25% pada berbanding dengan gasolin. Semasa beroperasi dengan
CNG keluaran engine seperti CO, CO2 dan HC sangat berkurangan tetapi keluaran NOx
meningkat dengan begitu tinggi berbanding dengan gasolin. Keputusan dan analisa yang
dibuat sangat berguna untuk kajian lanjut bagi tujuan pembangunan enjin gas pada masa
depan.
vii
TABLE OF CONTENTS
Page
SUPERVISOR’S DECLARATION
ii
STUDENT’S DECLARATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xii
LIST OF SYMBOLS
xiv
LIST OF ABBREVIATIONS
xvi
CHAPTER 1
INTRODUCTION
1.1
Introduction
1
1.2
Malaysian Scenario
2
1.3
Problem Statement
4
1.4
Objectives of the Research
5
1.5
Scope of the Project
1.6
Thesis Organization
CHAPTER 2
LITERATURE REVIEW
2.1
Introduction
6
2.2
World Fuel Supplies
6
2.3
CNG as Alternative Fuel
7
2.4
Characteristics of CNG
9
viii
2.5
2.4
Research on CNG Vehicle
11
2.5.1 Engine Performance
17
2.5.2 Emissions
20
2.5.3 Emissions of Engine
24
Summary
34
CHAPTER 3
METHODOLOGY
3.1
Introduction
28
3.2
Overall Research Methodology
28
3.3
Experimental Apparatus
29
3.4
Description of Apparatus
32
3.4.1 Combustion Analysis
34
3.4.2 Exhaust Gas Analysis
36
3.5
Experimental Procedure
38
3.6
Performance Parameter
41
3.6.1
Brake Power
41
3.6.2
Mean Effective Pressure
42
3.6.3
Air-Fuel Ratio
43
3.6.4
Specific Fuel Consumption
44
3.6.5
Efficiency
44
3.6
Summary
CHAPTER 4
46
RESULTS AND DISCUSSION
4.1
Introduction
47
4.2
Cylinder Pressure
47
4.3
Engine Performance
50
4.3.1
Air-Fuel Ratio
50
4.3.2
Torque
51
4.3.3
Power
53
ix
4.4
4.3.4
Fuel Consumption
56
4.3.5
Brake Mean Effective Pressure
59
4.3.6
Efficiency
60
4.3.7
Emissions of the Engine
Summary
CHAPTER 5
72
CONCLUSION AND RECOMMENDATIONS
5.1
Introduction
73
5.2
Conclusions
73
5.3
Recommendations for the Future Research
74
REFERENCES
75
APPENDICES
79
A
Dynamometer Load Cell Calibration
81
B
The Estimated of Maximum Gas Flowrate of Gas Flowmeter
81
C
Manual of TN SIC CNG Regulators
83
D
Calibration of Thermocouples
88
E
List of Publications
98
x
LIST OF TABLES
Table No.
Title
Page
1.1
The history of natural gas application for vehicle in Malaysia
2
2.1
Criteria affecting the suitability of alternative fuel
8
2.2
Dennis dart fuel requirement for various alternative fuel
8
3.1
Proton Magma 4G15 engine specification
32
4.1
Measured maximum peak pressure of gasoline and CNG at TDC
49
4.2
CNG torque reduction compare to gasoline
52
4.3
CNG brake power reduction compare to gasoline
55
4.4
CNG fuel flow rate reduction compare to gasoline
56
4.5
BSFC reduction of CNG compare to gasoline
58
4.6
BMEP reduction of CNG compare to gasoline
59
4.7
Brake thermal efficiency of CNG compare to gasoline
61
4.8
Typical value of mechanical efficiency of naturally aspirated SI
62
engine
xi
4.9
Typical value of volumetric efficiency of naturally aspirated SI
64
engine
4.10
CO concentration reduction of CNG compare to gasoline
66
4.11
CO2 concentration reduction of CNG compare to gasoline
67
4.12
HC concentration reduction of CNG compare to gasoline
69
4.13
Increment of NOx concentration reduction of CNG compare to
71
gasoline
xii
LIST OF FIGURES
Figure No.
Title
Page
2.4
Energy distributions
18
3.1
Flowchart of the studies
29
3.2
Schematic diagram of the engine test-bed
30
3.3
Figure of original test-rig
31
3.4
Dewetron CA combustion analyzer
35
3.5
Installed pressure sensor spark-plug
35
3.6
Bolted crank angle encoder
36
3.7
Crank angle encoder and data acquisition kit
36
3.8
Pressure sensor spark-plug
37
3.9
KEG-500 exhaust gas analyzer
38
4.1
Cylinder pressure distribution against CA degree of gasoline for
48
wide-open throttle condition
4.2
Cylinder pressure distribution against CA degree of CNG for
48
xiii
wide-open throttle condition
4.3
Air-fuel ratio at different engine speed for wide-open throttle
51
4.4
Torque at different engine speed for wide-open throttle
52
4.5
Indicated power at different engine speed for wide-open throttle
54
4.6
Brake power at different engine speed for wide-open throttle
55
4.7
Fuel flow rate at different engine speed for wide-open throttle
57
4.8
BSFC at different engine speed for wide-open throttle
58
4.9
BMEP at different engine speed for wide-open throttle
60
4.10
Brake thermal efficiency at different engine speed for wide-open
61
throttle
4.11
Mechanical efficiency at different engine speed for wide-open
63
throttle
4.12
Volumetric efficiency at different engine speed for wide-open
64
throttle
4.13
CO cocentration at different engine speed for wide-open throttle
66
4.14
CO2 concentration different engine speed for wide-open throttle
68
4.15
HC concentrayion at different engine speed for wide-open throttle
70
4.16
NOx concentraionat different engine speed for wide-open throttle
72
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