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Transcript of EFFECTS OF INJECTION PARAMETERS ON FUEL...
EFFECTS OF INJECTION PARAMETERS ON FUEL SPRAY
AND COMBUSTION CHARACTERISTICS OF A BIODIESEL
FUELLED DIESEL ENGINE
LAHANE SUBHASH VASUDEO
CENTRE FOR ENERGY STUDIES
INDIAN INSTITUTE OF TECHNOLOGY DELHI
OCTOBER 2012
EFFECTS OF INJECTION PARAMETERS ON FUEL SPRAY
AND COMBUSTION CHARACTERISTICS OF A BIODIESEL
FUELLED DIESEL ENGINE
by
LAHANE SUBHASH VASUDEO
CENTRE FOR ENERGY STUDIES
Submitted
In fulfillment of the requirements of the degree of
Doctor of Philosophy
to the
INDIAN INSTITUTE OF TECHNOLOGY DELHI
OCTOBER 2012
i
CERTIFICATE
The thesis entitled “Effects of Injection Parameters on Fuel Spray and Combustion
Characteristics of a Biodiesel Fuelled Diesel Engine” being submitted by Mr. Lahane
Subhash Vasudeo to the Indian Institute of Technology Delhi, for the award of the degree
of Doctor of Philosophy, is a record of bona fide research work carried out by him. He
was worked under my supervision, and has fulfilled the requirements for the submission
of this thesis, which has attained the standard required for a Ph. D. degree of the Institute.
The results presented in this thesis have not been submitted elsewhere for the award of
any degree or diploma.
I certify that he has pursued the prescribed course of research.
October 2012 Dr. K. A. Subramanian
Associate Professor, Centre for Energy Studies
Indian Institute of Technology Delhi
Hauz Khas, New Delhi – 110 016
ii
ACKNOWLEDGEMENTS
With all due respect, I would like to express my deep sense of gratitude, indebtedness,
and thankfulness to my supervisor and guide Dr. K. A. Subramanian for his constant
and consistent, inspiring guidance and utmost co-operation at every stage, which
culminated in successful completion of my research work. I, without any doubt in my
mind, consider myself most fortunate to work under Dr. K. A. Subramanian’s guidance.
I heartily thank almighty God to give me an opportunity to work under Dr. K. A.
Subramanian’s able guidance. To him, I am forever, indebted.
I am very much thankful to Prof. R. P. Sharma, Head, CES for providing me required
research facilities. I would also thank Prof. S. C. Kaushik (Former Head, CES) for
providing me facilities during the initial period of my research work.
My sincere thank to all my Student Research Committee (SRC) members of Prof. R. P.
Sharma (SRC-Chairman), Prof. T. S. Bhatti (Ph. D. Coordinator, CES), Prof. (Retd.) J.
P. Subrahmanyam and Prof. (Retd.) M. K. G. Babu for their valuable suggestions on
my research work. Their suggestions helped me immensely to improve the quality of my
research work.
I would like to thank Prof. L. M. Das for his encouragement on my research work. I
thank to Prof. M. G. Dastidar for permitting me to use her lab facilities for certain
measurement required for my research work. I also would like to thank Faculty In-
charge and staff for use Central Facilities, IIT Delhi for my research work.
iii
My sincere thank to Department of Science and Technology (DST), Council of
Scientific and Industrial Research (CSIR) and Industrial R & D, IIT Delhi for
supporting fund for presenting my research work at American Society of Mechanical
Engineering (ASME) International Conference at Torino, Piemonte, Italy.
I thank Centre for Energy Studies staff member Mrs. N. K. Puri and Mrs. Harjeet Kaur
Narula for official work related to my research work.
I am grateful to my colleagues and my friends Dr. C. H. Biradar, Dr. Reji Mathai, Dr.
Karu Ragupathy, Mr. Venkateswrlu Chintala, Mr. Sunmeet Singh, Mr. Chandu
Madankar, Dr. Lalit Joshi, Mr. R. Balasubramanian, Mr. Salvi, Mr. Ramesh
Jeeragal and Mr. Ashok for their cooperation.
My special thanks go to Mr. Charan R., Mr. Vaibhav V. Jadhav and Mr. Vinaya C.
Mathad for their support and conducive cooperation during my experimental work.
I also would like to convey my sincere thanks to Mr. Batra and Mr. Attar Sing from of
Engines and Unconventional Fuels Laboratory, Mr. Bhaskar and Mr. Ramakrishna
from Workshop and Mr. Shankar Lal Sharma from IT Lab, CES for their kind support
and help in completing this research work.
I have no word to express my sentiments for my parents and in-laws, Shri Vasudeo S.
Lahane, Smt Rukhmina V. Lahane and Shri Prabhakar N. Kakde, Smt. Shalini P.
Kakde who always loved and encouraged me for higher education.
I have no befitting words to express deep sentiments towards my Wife: Smt. Sheetal
Subhash Lahane, Son: Mr. Bhargav Subhash Lahane and Daughter: Ms. Nityasree
iv
Subhash Lahane for their whole hearted support and patience during the period of my
study/research work.
I also would like to extend my sentiments towards my Brother: Shri. Narendra Vasudeo
Lahane, Sister- in- law: Smt. Anjali Narendra Lahane and Niece: Ms. Shrusti Lahane
for their kind support during the period of my study.
Last but not least, I would like to express my thanks and deep gratitude to the
omnipresent almighty God by whose grace, my dream of completing this thesis has come
true.
New Delhi Lahane Subhash Vasudeo
October 2012
v
ABASTRACT
This research work is aimed at study of effect of injection parameters (in-line fuel
injection pressure, injection delay, dynamic injection timing (DIT) and injection duration)
on fuel spray, combustion, performance and emission characteristics of a diesel engine
(7.4 kW rated power output) for different biodiesel-diesel blends (B5 to B100). CO, HC
and smoke emissions decreased with all biodiesel-diesel blends at all loads. However,
NOx emission increased with all biodiesel-diesel blends due to higher spray penetration,
oxygen content, advancement in dynamic injection timing and increase in in-cylinder
temperature. At the rated load, NOx and spray penetration increased from 6.24 g/kW-hr
and 34.28 mm with base diesel to 7.39 g/kW-hr and 36.29 mm with B20 and 8.07 g/kW-
hr and 37.5 mm with B100 respectively. The spray penetration increases with biodiesel
due to increase in in-line fuel injection pressure (due to higher bulk modulus) resulting in
a probability of wall impingement and high NOx emission. The optimum biodiesel-diesel
blend based on no wall impingement and less increase in NOx emission (B15: 4.1 %;
B20: 15.6 % and B100: 22.8 %) in an unmodified (conventional) diesel engine is up to
B15 whereas B20 is found to be the critical limit of wall impingement (within uncertainty
limits of ±1. 3 %). However, the wall impingement and NOx emission is higher with
higher biodiesel-diesel blends beyond B20.
Further experimental tests were conducted on the diesel engine with a hardware
modification (injection timing (retard and advance), injection pump’s plunger size, nozzle
configuration (number of holes and size) and nozzle opening pressure) for B20 in order to
reduce wall impingement and NOx emission at source level.
The retarded injection timing in a modified engine decreases the in-line fuel injection
pressure resulting in lower spray penetration. No wall impingement was observed with
retarded injection timing due to higher distance between the bowl and injector tip than
spray penetration. However, the retarded injection timing does not give desirable results
except no wall impingement and NOx (4.82 g/kW-hr) as it increases BSEC, CO, HC, and
smoke.
vi
The pump’s plunger diameter was varied from 9.5 mm (base) to 9 mm and 8.7 mm. As
the volume of fuel pumped by the plunger per unit crank angle would influence the
injection pressure at the nozzle, the decrease in plunger diameter decreases the in-line
fuel injection pressure. The modification of pump’s plunger diameter gives beneficial
results in terms of lower NOx (5.01 g/kW-hr) and no probability of wall impingement.
However, BSEC, CO, HC and smoke emissions increased with modified pump’s plunger.
The injector nozzle configuration was changed from 0.19 mm (hole diameter) × 5 holes
(base) to 0.188 mm (hole diameter) × 6 holes (modified). The in-line fuel injection
pressure decreased with modified nozzle due to lower fuel quantity per hole results in
lower spray penetration and no wall impingement. NOx and smoke emissions decreased
with modified nozzle configuration. The reasons for reduction in NOx emission is mainly
due to the automatic retardation of DIT, lower spray penetration, and lower localized in-
cylinder temperature. The smoke emission decreased due to the smaller sauter mean
diameter (SMD) resulting in better mixing and vaporization. In the final phase, the tests
were conducted with hydrogen as an additive (7.7 % and 11.2 % energy share). The in-
line fuel injection pressure decreased with hydrogen energy share due to reduction in
main fuel quantity results in lower spray penetration and no wall impingement. All the
emissions decreased up to 11.2 % energy share. However, NOx emission increased with
14 % energy share due to dominant effect of higher in-cylinder pressure and temperature.
The salient points emerged from the study are that the diesel engine fueled with B5 to
B15 does not have a probability of wall impingement where as it is critical (uncertainty:
±1.3%) with B20 but the probability increases with higher biodiesel-diesel blends (B25,
B50 and B100). Techniques such as the injection timing retardation and plunger
modification do not give desirable results except no wall impingement and NOx
reduction. The modified injector configuration gives the best results in terms of lower
NOx and wall impingement probability as compared to the all techniques. Overall, it can
be concluded that modification of injector nozzle configuration of a diesel engine for use
of biodiesel-diesel blend is necessary for reducing NOx emission at source level along
with the additional benefit of BSEC and smoke reduction without problem of wall
impingement.
vii
CONTENTS
Page No.
Certificate i
Acknowledgement ii
Abstract v
Contents vii
List of Figures xv
Last of Tables xxvii
Nomenclature xxix
Chapter 1 INTRODUCTION 1-15
1.1 Injection and fuel spray characteristics of diesel engines 2
1.1.1 Spray break-up length 5
1.1.2 Spray cone angle 5
1.1.3 Sauter mean diameter (SMD) 5
1.1.4 Spray penetration 6
1.1.5 Wall impingement 6
1.1.6 Air entrainment 7
1.2 Combustion characteristics of diesel engines 7
1.3 Performance and emission characteristics of diesel engines 9
1.4 Control strategies for solving problems higher NOx emission
and more probability of wall impingement in a biodiesel
13
viii
fuelled diesel engines
Closure 14
Chapter 2 LITERATURE SURVEY AND OBJECTIVES 16-49
2.1 Effect of biodiesel-diesel blends on injection and spray
characteristics of a diesel engine
17
2.2 Available models/correlations for analysis of spray
characteristics of a diesel engine for base diesel
20
2.2.1 Available models for analysis of spray break-up length 20
2.2.2 Available models for analysis of spray cone angle 22
2.2.3 Available models for analysis of sauter mean diameter
(SMD)
24
2.2.4 Available models for analysis of spray penetration 26
2.2.5 Available models for analysis of air entrainment 29
2.2.6 Available models for analysis of vaporization 30
2.3 Wall impingement 32
2.4 Ignition and combustion characteristics of a diesel engine 36
2.5 Performance and emission characteristics of a diesel engine
using biodiesel-diesel blends
39
2.6 NOx emission reduction technology for diesel engines 43
2.7 Further improvement of performance and emission
characteristics of diesel engines using hydrogen as an
44
ix
additive
2.8 Research gap 45
Closure 48
2.9 Objectives 49
Chapter 3 METHODOLOGY AND EXPERIMENTAL DETAILS 50-72
3.1 Methodology 51
3.2 Experimental details 54
3.2.1 Biodiesel preparation using Transesterification process 54
3.2.2 Fuel quality analysis of biodiesel and base diesel 55
3.2.3 Development of experimental setup 59
3.2.4 Baseline data generation for diesel, B5, B10, B15, B20, B25,
B50 and B100
62
3.2.5 Study of the effect of fuel spray penetration on wall
impingement on the piston bowl of the engine
63
3.2.6 Combustion characteristics of the diesel engine 64
3.2.7 Selection of optimum biodiesel-diesel blend for further
studies on the engine with hardware modification
65
3.2.8 Description of injection parameters for reduction in NOx and
wall impingement of biodiesel (B20) fuelled diesel engine
65
3.2.9 Further reduction in fuel consumption, smoke, CO2 and
NOx of biodiesel fuelled diesel engine using hydrogen as an
67
x
additive
3.3 Uncertainty analysis 69
3.3.1 Uncertainty analysis of measured parameters 69
3.3.2 Uncertainty analysis of calculated parameters 71
Closure 72
Chapter 4 RESULTS AND DISCUSSION 73-195
4.1 Injection and fuel spray characteristics of the diesel engine 74
4.1.1 Analysis of injection and fuel spray characteristics for
different biodiesel-diesel blends and base diesel
75
4.1.1.1 Analysis of spray break-up length 84
4.1.1.2 Analysis of spray cone angle 86
4.1.1.3 Analysis of sauter mean diameter (SMD) 87
4.1.1.4 Analysis of spray penetration 90
4.1.1.5 Analysis of air entrainment 92
4.1.1.6 Analysis of wall impingement on piston bowl
with respect to crank angle
93
4.1.1.7 Analysis of vaporization 98
4.1.2 Analysis of injection and spray characteristics with retarded
injection timing for B20 fuel
103
4.1.3 Analysis of injection and spray characteristics with different
diameters of pump plunger for B20 fuel
107
xi
4.1.4 Analysis of injection and spray characteristics with modified
nozzle configuration for B20 fuel
111
4.1.5 Analysis of injection and spray characteristics with different
nozzle opening pressures (NOP) for B20 fuel
117
4.1.6 Analysis of injection and spray characteristics with advanced
injection timing at NOP: 300 bar for B20 fuel
120
4.2 Combustion characteristics of the diesel engine 123
4.2.1 Analysis of combustion characteristics for B5, B10, B15,
B20, B25, B50, B100 and base diesel
123
4.2.2 Development of Physical and Chemical ignition delay
correlation
131
4.2.2.1 Development of Physical ignition delay (PID)
correlation
133
4.2.2.2 Development of Chemical ignition delay (CID)
correlation
134
4.2.2.3 Development of Total ignition delay (TID)
correlation
134
4.2.2.4 Validation of the developed ignition delay
correlation with measured experimental data
135
4.2.3 Analysis of combustion characteristics with retarded
injection timing for B20 fuel
139
4.2.4 Analysis of combustion characteristics of the engine with 142
xii
modified plunger (9.5 mm (base) to 9 mm and 8.7 mm
diameter) for B20 fuel
4.2.5 Analysis of combustion characteristics with modified nozzle
configuration (6 × 0.188mm) for B20 fuel
146
4.2.6 Analysis of combustion characteristics with different nozzle
opening pressures (NOP) for B20 fuel
149
4.2.7 Analysis of combustion characteristics with advanced
injection timing at NOP: 300 bar for B20 fuel
152
4.3 Performance and emission characteristics of the diesel
engine
155
4.3.1 Analysis of performance and emission characteristics for B5,
B10, B15, B20, B25, B50, B100 and base diesel fuel
155
4.3.2 Analysis of performance and emission characteristics of the
diesel engine with retarded injection timing for B20 fuel
167
4.3.3 Analysis of performance and emission characteristics of the
engine with different diameter of pump plunger for B20 fuel
170
4.3.4 Analysis of performance and emission characteristics with
modified nozzle configuration (6 holes) for B20 fuel
173
4.3.5 Analysis of performance and emission characteristics with
different nozzle opening pressures (NOP) for B20 fuel
175
4.3.6 Analysis of performance and emission characteristics with
advanced injection timing for 6 holes nozzle at 300 bar NOP
179
xiii
for B20 fuel
4.3.7 Further improvement of performance and emission
characteristics of the engine using hydrogen as an additive
182
4.4 Selection of suitable technology for BSEC and NOx
reduction of a biodiesel fuelled diesel engine
190
Closure 193
Chapter 5 CONCLUSIONS 196-203
5.1 Conclusions 197
5.1.1 Injection and fuel spray characteristics of the diesel engine 197
5.1.1.1 Comparison of injection and fuel spray
characteristics for biodiesel-diesel blends (B5, B10,
B15, B20, B25, B50 and B100) with base diesel
197
5.1.1.2 Comparison of injection and fuel spray
characteristics of a diesel engine with 5 holes (base)
and 6 holes (modified) nozzle
199
5.1.2 Combustion characteristics of the diesel engine 200
5.1.2.1 Comparison of combustion characteristics for
biodiesel-diesel blends (B5, B10, B15, B20, B25,
B50 and B100) with base diesel
200
5.1.2.2 Comparison of combustion characteristics of a
diesel engine with 5 holes (base) and 6 holes
200
xiv
(modified) nozzle configuration
5.1.3 Performance and emission characteristics of a diesel engine 200
5.1.3.1 Comparison of performance and emission
characteristics for biodiesel-diesel blends (B5, B10,
B15, B20, B25, B50 and B100) with base diesel
201
5.1.3.2 Comparison of performance and emission
characteristics of a diesel engine with 5 holes (base)
and 6 holes (modified) nozzle for B20
201
5.1.4 Fuel modification: Hydrogen as additive 202
5.2 Future scope of the study 202
References 204-217
Appendices 218-225
Appendix 1 219
Appendix 2 220
Appendix 3 221
Appendix 4 223
Appendix 5 224
Publication 226
Bio-data 228