CHARACTERIZATION OF BIODIESEL AS A FUEL IN A COMPRESSION IGNITION

(CI) ENGINE WITH ADDITIVES

MOHD HAFIZIL BIN MAT YASIN

A report submitted in partial fulfilment of the requirements

for the award of the degree of

Master of Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI MALAYSIA PAHANG

NOVEMBER 2012

v

ABSTRACT

Compression ignition engines have been used widely in the transportation sector and

power generation for the decades. These engines are less fuel consumed with higher brake

thermal efficiency. However, compression ignition engines produce higher pollution in

NOx and PM emission as well as cause several negative drawbacks to the environment.

Most countries in the world have regulated several regulations to reduce the emission from

the engines. Other than that, the introduction of biodiesel in the engines is beneficial and

proven to reduce the emission significantly. However, biodiesel has higher density and

viscosity with lower heating value as compared to mineral diesel. Fuel additives are among

other methods that proven to modify the properties of biodiesel to be comparable with

mineral diesel without doing any engine modification. Although fuel additives’ ability to

reduce harmful emissions is well known in the literature, the mechanism for these

additives is not well understood when operated in the four-stroke, four-cylinder diesel

engines. Two alcohol-based additives, methanol and ethanol were diluted with B 20 blend

(20% biodiesel + 80% mineral diesel) with the formulation of 5% by volume. The test

fuels; mineral diesel, B100 (palm-diesel), B20 blend and B20-alcohol blends (B20 E5 and

B20 M5) were investigated on a Mitsubishi 4D68 four stroke, four-cylinder water-cooled

diesel engine incorporating sensors for in-cylinder pressure measurement and

thermocouples. There were two operating modes dealing with these fuels, which the first

mode been conducted on increasing engine speeds at 50% throttle position. While as for

the second mode, these fuels were operated at three different engine loads, 0.05 MPa, 0.4

MPa and 0.7 MPa with the engine constant speed of 2500 rpm. The effect of test fuels on

brake power, brake specific fuel consumption (BSFC), brake thermal efficiency (BTE),

combustion (in-cylinder pressure, rate of heat release, cylinder temperature) and NOx, NO,

CO and CO2 emissions were investigated. Results found that the performance of diesel

engine improved with the use of alcohol (ethanol and methanol) in the B20 blends

especially in comparison to mineral diesel, B100 and B20. Overall, the results indicated

that when compared to mineral diesel, B100, B20, B20 E5 and B20 M5 have higher brake

thermal efficiency. The use of alcohol as a fuel additive in the B20 blend has improved the

combustion characteristics when the loads were applied to the engine. Besides, the exhaust

emission for the B20 E5 and B20 M5 were fairly reduced when compared to mineral

diesel.

vi

ABSTRAK

Enjin cucuhan mampatan telah lama digunakan secara meluas dalam sektor pengangkutan

dan penghasilan kuasa. Enjin ini menggunakan bahan api yang minimum dengan

kecekapan brek termal yang tinggi. Walaubagaimanapun, enjin cucuhan mampatan

menghasilkan pencemaran NOx dan zarah terampai (PM) yang tinggi serta kesan yang

negatif terhadap alam sekitar. Kebanyakan negara di dunia telah menguatkuasakan

beberapa peraturan untuk mengurangkan kadar pencemaran daripada enjin tersebut. Selain

itu, penggunaan biodiesel sebagai bahan api alternatif dalam enjin diesel dan terbukti untuk

mengurangkan kadar pencemaran. Walaubagaimanapun, biodiesel mempunyai nilai

ketumpatan dan kelikatan yang lebih tinggi serta nilai pemanasan yang lebih rendah

berbanding diesel mineral. Additif bahan api merupakan antara kaedah yang terbukti bagi

mengubahsuai ciri – ciri bahan api biodiesel agar setanding dengan diesel mineral tanpa

melakukan pengubahsuaian terhadap enjin diesel. Walaupun keupayaan additif untuk

mengurangkan pencemaran banyak dibincangkan namun mekanisme additif tersebut masih

belum difahami apabila digunakan dalam enjin diesel empat lejang empat silinder. Dua

additif jenis alkohol, etanol dan metanol telah dilarutkan bersama B20 (campuran 20%

biodiesel dan 80% diesel mineral) dengan formulasi campuran 5%. Bahan api campuran

bersama alkohol dan biodiesel-diesel (B20 E5 dan B20 M5), diesel mineral, B100 (palm-

diesel) dan B20 telah diuji menggunakan enjin diesel Mitsubishi 4D68 jenis 4 lejang 4

silinder dengan sistem penyejukan air yang dilengkapi penderia mengukur tekanan dalam

silinder serta termogandingan suhu. Terdapat dua jenis pengujian enjin menggunakan

bahan api tersebut; iaitu pengujian enjin pertama dijalankan dengan meningkatkan kelajuan

enjin bermula 1500 rpm sehingga 3500 rpm pada 50% kedudukan pendikit enjin.

Manakala pengujian enjin yang kedua, bahan api tersebut dioperasikan pada tiga bebanan

berbeza iaitu 0.05 MPa, 0.4 MPa dan 0.7 MPa menggunakan kelajuan enjin malar, 2500

rpm. Kesan penggunaan bahan api tersebut terhadap kuasa brek, penggunaan bahan api

brek khusus (BSFC), kecekapan brek termal (BTE), pembakaran (tekanan dalam silinder,

kadar penyingkiran haba, suhu silinder) dan penghasilan gas NOx, NO, CO dan CO2 telah

direkodkan dan di analisa dalam kajian ini. Keputusan eksperimen menunjukkan bahawa

prestasi enjin diesel meningkat dengan penggunaan alkohol (etanol dan metanol) dalam

bahan api B20 apabila dibandingkan dengan diesel mineral dan bahan api B20. Secara

keseluruhan, keputusan menunjukkan B100, B20, B20 E5 dan B20 M5 mempunyai

kecekapan brek termal lebih tinggi berbanding dengan diesel mineral. Penggunaan alkohol

sebagai additif dalam bahan api B20 telah meningkatkan ciri – ciri pembakaran dalam

silinder apabila bebanan dikenakan pada enjin. Selain itu, pengeluaran gas ekzos telah

berkurang bagi B20 E5 dan B20 M5 apabila dibandingkan dengan mineral diesel dalam

pengujian enjin tersebut.

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 xiv

LIST OF FIGURES xv

LIST OF SYMBOLS xix

LIST OF ABBREVIATIONS xxi

CHAPTER 1 INTRODUCTION

1.1 Introduction 1

1.2 Overview of emission regulation and controls 4

1.3 Project overview 5

1.4 Problem statement 6

1.5 Objective of the study 6

1.6 Scope of the study 7

1.7 Research methodology 7

1.8 Report outline 9

viii

CHAPTER 2 LITERATURE REVIEW

2.1 Diesel engine 11

2.1.1 History of diesel engines 11

2.1.2 Types of diesel engine 12

2.1.3 Diesel engine applications 14

2.1.4 Diesel engine technology 15

2.2 Diesel and its properties 16

2.2.1 Cetane number 18

2.2.2 Viscosity 18

2.2.3 Density 19

2.2.3 Heating value 19

2.2.4 Aromatic content 20

2.2.5 Sulfur 20

2.2.6 Specific gravity (API Gravity) 21

2.2.7 Cloud point, pour point and cold filter clogging point 21

2.2.8 Flash point and vapour pressure 21

2.3 Diesel engine exhaust emissions 22

2.3.1 Oxides of nitrogen (NOx) 22

2.3.2 Carbon monoxide (CO) 24

2.3.3 Unburned hydrocarbons (UHCs) 24

2.3.4 Particulate matter (PM) 25

2.3.5 Polycyclic aromatic hydrocarbons (PAHs) 26

2.4 Biodiesel as an alternative fuel for diesel engines 27

2.4.1 Biodiesel production, policies and standardizations 27

2.4.2 Advantages of biodiesel use in diesel engines 32

2.4.3 Palm-diesel (palm methyl ester) as a future biodiesel fuel for

diesel engines

33

2.4.4 Performance of biodiesel as alternative fuels in diesel

engines

34

2.4.5 Exhaust emissions from the combustion of biodiesel 36

ix

2.5 Fuel additives 38

2.5.1 Types of fuel additives 39

2.5.2 Performance and emissions of biodiesel fuels with alcohol

based additives

40

2.6 Engine testing analysis 42

2.6.1 Brake power and torque 42

2.6.2 Brake specific fuel consumption (BSFC) 43

2.6.3 Brake mean effective pressure (BMEP) 44

2.6.4 Indicated mean effective pressure (IMEP) 44

2.6.5 Brake thermal efficiency (BTE) 45

2.6.6 Correction factors 45

2.7 Combustion analysis 46

2.7.1 Ignition delay period 47

2.7.2 Premixed burning period 47

2.7.3 Diffusion burning period 48

2.7.4 After burning period 48

2.7.5 Combustion summary 49

2.8 Measured and calculated parameters in the combustion analysis 49

2.8.1 In-cylinder pressure 49

2.8.2 Rate of heat release (RoHR) 50

2.8.3 Air flow ratio (AFR) 52

2.8.4 In-cylinder gas temperature 53

2.8.5 Mass fraction burn (MFB) 53

2.9 Summary 54

CHAPTER 3 EXPERIMENTAL FACILITY SET-UP AND

APPARATUS

3.1 Introduction 55

x

3.2 Engine testing apparatus 57

3.2.1 Engine mapping performance 57

3.2.2 Dynamometer and drive trains 59

3.2.3 Engine and dynamometer cooling systems 62

3.2.4 Fuel delivery and measurement system 65

3.2.5 Engine wiring 66

3.2.6 Air intake measurement system 67

3.2.7 Temperature monitoring and measuring 68

3.2.8 In-cylinder pressure data acquisition 68

3.2.9 Ambient temperature and relative humidity data acquisition 73

3.3 Exhaust gas monitoring and analysis 74

3.3.1. Exhaust gaseous measurement 74

3.4 Test fuels and lubricant 76

3.5 Test additives 77

3.6 Test-operating conditions 78

3.7 Test matrices 79

CHAPTER 4 FUEL PROPERTIES AND ENGINE PERFORMANCE

OF THE DIESEL ENGINE

4.1 Introduction 80

4.2 Physical, chemical and other related properties of the test fuels 80

4.2.1. Density 81

4.2.2 Viscosity and lubricity 81

4.2.3 Heat value 82

4.2.4 Cetane number 82

4.2.5 Summary 83

4.3 Engine performance 83

4.3.1 Engine performance curve 84

xi

4.3.2 Engine brake power results 86

4.3.3 Brake specific fuel consumption (bsfc) 88

4.3.4 Brake thermal efficiency (BTE) analysis 90

CHAPTER 5 COMBUSTION CHARACTERISTICS OF THE

ENGINE

5.1 Introduction 92

5.2 Combustion characteristics of the engine 92

5.3 Peak cylinder pressure for the test fuels 93

5.4 Rate of pressure rise (RoPR) for the test fuels 96

5.5 Cylinder temperature for the test fuels 100

5.6 Peak cylinder pressure against volume displacement, dm3 103

5.7 Rate of heat release (RoHR) for the test fuels 107

5.8 Mass fraction burned (MFB) for the test fuels 111

5.9 Summary 126

CHAPTER 6 EMISSION CHARACTERISTICS OF THE

ENGINE

6.1 Introduction 116

6.2 Exhaust emissions 116

6.3 Brake specific NOx (BSNOx) emissions 118

6.4 Brake specific NO (BSNO) emissions 120

6.5 Brake specific carbon monoxide (BSCO) emission 121

6.6 Brake specific carbon dioxide (BSCO2) emission 123

xii

CHAPTER 7 CONCLUSION

7.1 Conclusion 125

7.2 Recommendations 127

7.2.1 Accommodate more pressure transducer 127

7.2.2 Simulation versus experiments 127

7.2.3 Transient test condition 128

7.2.4 Test at higher biodiesel proportions 128

REFERENCES 129

APPENDICES

A1 Past, current and proposed future for European emission standards 140

B1 ASTM and MS test methods for diesel fuel properties 141

B2 Properties of different vegetable oils (Ayhan Demirbas, 2003) 142

B3 Fatty acid composition (% mass) from different types of biodiesel

oils (Singh & Singh, 2010)

143

C1 ECB-200 dynamometer specification 144

C2 Specification of dynamometer cooling tower 145

C3 AIC fuel flow meter specification 146

C4 Specification of Meriam laminar flow element (LFE) 147

C5 K-type thermocouple probe specification 148

C6 Charge module specification 149

C7 Specification of Kistler crank angle encoder type 2613B 150

C8 DEWE-800 DAQ system specification 151

C9 Specification of DEWE-Orion 1624 data acquisition card 152

C10 EL-USB-RT data logger specification 153

C11 Test-operating conditions 154

C12 Test matrix for fuel testing at the increasing speeds with a partial 155

xiii

engine throttle position

C13 Test matrix for fuel testing at three different engine loads with a

constant engine speed of 2500 rpm

156

D1 Measured fuel properties of mineral diesel, B100 (palm-diesel),

B20, B20 E5 and B20 M5

157

D2 Engine performance results for test fuels 158

E1 Brake specific nitrogen oxide (NOx) concentrations (g/kW-hr) 159

E1 Brake specific nitrogen monoxide (NO) concentrations (g/kW-hr) 159

E1 Brake specific carbon monoxide (CO) concentrations (g/kW-hr) 159

E2 Brake specific carbon dioxide (BSCO2) concentrations (g/kW-hr) 160

F1 List of publications 161

xiv

LIST OF TABLES

Table No. Title Page

3.1 Engine specifications 58

3.7 In-cylinder pressure transducer specification 70

3.13 Specification for Signal Instrument gas analyzer 75

3.14 Accuracy measurement for Kane gas analyzer 75

3.15 Test fuels properties 77

3.16 Physical properties of ethanol and methanol 78

xv

LIST OF FIGURES

Figure No. Title Page

2.1 Four-stroke diesel engine cylinder cycles (Shankar,

2011)

13

2.2 Comparison between DI and IDI diesel engine (Bosch,

1996)

14

2.3 Typical diesel chemical composition Cetane or n-

hexadecane, C16H34

17

2.4 Formation of particulate matter (PM) (Maricq, 2007) 26

2.5 Polycyclic aromatic hydrocarbons (PAHs) molecule

structure (Gilbert, 2004)

27

2.6 A basic transesterification process (Tyson, 2009) 28

2.7 A transesterification process with methanol as a catalyst

(Ma & Hanna, 1999)

29

2.8 Palm oil is transesterified into palm-diesel 34

2.9 Pressure curve in the cylinder 50

3.1 Engine testing facility lay out 56

3.2 Engine test rig 57

3.3 Engine characteristics at a partial engine throttle position 58

3.4 (a) Dynalec dynamometer (b) Throttle position lever 59

3.5 A Dynalec dynamometer controller 60

3.6 (a) Engine dynamometer performance curve (b) Engine

dynamometer torque curve

61

xvi

3.7 A hook joint cardan prop shaft 62

3.8 Engine cooling system diagram 63

3.9 (a) Engine cooling system (b) Dynamometer cooling

tower

64

3.10 (a) AIC fuel flow meter (b) A board computer type BC-

3033

65

3.11 Engine wiring diagram 66

3.12 Air intake measurement in a diesel engine 67

3.13 (a) Thermocouple locations at the exhaust extractors (b)

Thermocouple locations at air intake and engine cooling

system

68

3.14 A schematic diagram of the engine test bed and

instrumentation

69

3.15 A Kistler 6041 ThermoCOMP pressure transducer 70

3.16 (a) Kistler crank angle encoder type 2613B1 (b) Kistler

signal conditioner type 2613B2

71

3.17 Schematic diagram and wirings of in-cylinder pressure

data acquisition

71

3.18 Cylinder pressure measurement using DEWECa

graphical user interface (GUI)

72

3.19 (a) EL-USB-RT data logger (b) EL-USB-RT software

logger interface

73

3.20 (a) A Signal instrument gas analyzer (b) A KANE gas

analyzer

74

3.21 Gas analyzer flow channel location 76

4.1 Density of the test fuels (M.H. Mat Yasin, 2012) 81

4.2 A Mitsubishi 4D68 diesel engine performance curves at a

partial engine throttle position

85

xvii

4.3 Engine brake power at increasing engine speeds, partial

throttle position

87

4.4 Brake specific fuel consumption (BSFC) for the

increasing speeds at a partial throttle position

88

4.5 Brake thermal efficiencies (BTE) relative to increasing

speeds at 50% throttle position

90

5.1 Peak cylinder pressure curve with engine load, 0.05 MPa

at 2500 rpm

93

5.2 Peak cylinder pressure curve with engine load, 0.4 MPa

at 2500 rpm

94

5.3 Peak cylinder pressure with engine load, 0.7 MPa at 2500

rpm

95

5.4 Rate of pressure rise with engine load, 0.05 MPa at 2500

rpm

97

5.5 Rate of pressure rise with engine load, 0.4 MPa at 2500

rpm

98

5.6 Rate of pressure rise with engine load, 0.7 MPa at 2500

rpm

99

5.7 Cylinder temperatures at with engine load, 0.05 MPa at

2500 rpm

100

5.8 Cylinder temperatures with engine load, 0.4 MPa at 2500

rpm

101

5.9 Cylinder temperatures with engine load, 0.7 MPa at 2500

rpm

102

5.10 Peak in-cylinder pressure against volume displacement

with engine load, 0.05 MPa at 2500 rpm

104

5.11 Peak in-cylinder pressure relative to volume

displacement with engine load, 0.4 MPa at 2500 rpm

105

5.12 Peak in-cylinder pressure against volume displacement

with engine load, 0.7 MPa at 2500 rpm

106

xviii

5.13 Rate of heat release (RoHR) with engine load, 0.05 MPa

at 2500 rpm

108

5.14 Rate of heat release rate with engine load, 0.4 MPa at

2500 rpm

109

5.15 Variations of heat release rate with engine load, 0.7 MPa

at 2500 rpm

110

5.16 Mass fraction burned (MFB) with engine load, 0.05 MPa

at 2500 rpm

112

5.17 Mass fraction burned (MFB) with engine load, 0.4 MPa

at 2500 rpm

113

5.18 Mass fraction burned (MFB) with engine load, 0.7 MPa

at 2500 rpm

114

6.1 BSNOx emissions with engine loads for different test

fuels at 2500 rpm

118

6.2 BSNO emissions with engine loads for different test

fuels at 2500 rpm

120

6.3 BSCO emissions with engine loads for different test fuels

at 2500 rpm

121

6.4 BSCO2 emissions with engine loads for different test

fuels at 2500 rpm

123

xix

LIST OF SYMBOLS

g m/s2 Acceleration due to

gravity

ma kg/s Air mass flow rate

l - Air excess ratio

N rpm Crankshaft rotational

speed

r kg/m3 Density

μ kg/ms Dynamics viscosity

Pb kW Engine brake power

Tb Nm Engine brake torque

h % Engine thermal efficiency

mf kg/s Fuel mass flow rate

F Fuel-to-air equivalence ratio

V cm3 Instantaneous volume of the

engine cylinder

p bar In-cylinder pressure

_q delay deg Ignition delay

k joules Kinetic energy

pmax bar Peak in-cylinder pressure

pdrop bar Pressure drop

g Ratio of specific heats

Rswirl - Swirl ratio

t s Time

Total m kg/s Total air mass flow rate

V V Voltage signal

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

Fossilized energy has contributed the most impact of the economic development

in the world through the transportation sector and energy conversion sector. Middle

East region has supplied about half of oil production in the world and the rest come

from the central Asia region and America continent. However, the uncertain of oil

prices have given the side effect to the world economic with the factors of instability

political situation especially in the Middle East region and the decrease of crude oil

production reserve. This scenario has started in early 1970 with the oil price increased

to US Dollar 110 per barrel and another highest oil price recorded was in 2009 with

over US Dollar 135 per barrel (Hamilton, 2011).

The erratic increase in oil prices was reflected due to Arab-Israel War and the

Iran revolution that held between year 1965 and 1975. The economics of depending

mostly on imported fuels have grown in recent years as oil prices have become

unstable, doubling in less than two years the price of 2004 and reaching in 2006 oil

prices (Aleklett et al., 2010). This trend of events has shown that the oil prices will not

be permanent and could be escalate again depending on world instability situation and

increasing demand factor. Uncertain oil prices in the oil market have enhanced the

growth of commercial viability of alternatives fuels that can replace the fossilized fuels

without any modification to the engines.

2

Moreover, in the environmental side, the use of fossilized energy especially in

the transportation where at least 25% has contributed to the increasing of toxic gas and

affected and greenhouse emission. With the growing awareness of energy-pollution and

a climate change consequence, as well as complying to the Kyoto Protocol that targets

the use of less energy pollution from emitting energy source which is a clear message

to the global for a change towards more sustainable energy production and conservation

(Goldemberg J., 2004).

In year 2030, transportation sector will be the most emitting factor for the world

with the growth demand of vehicles on the road (Birol, 2010). Emission contents which

released from the vehicles show the linear scale with the fuel consumption where

today’s vehicles are mostly running with fossilized fuels. Following the trend, the

increase of GHG also will be projected to 50% by 2030. The use of fossilized fuels has

released the toxic gas including carbon dioxide (CO2), nitrogen oxide (NOx), unburned

hydrocarbon (UHC) and unseen particulate matters. This combination of harmful

portion can cause unhealthy air that affects to the human respiratory system and thick

fog that surround the area with low vision range. According to Vardoulakis et al., the

higher contents of particulate can result cancer, respiratory diseases such as asthma,

allergic and others that can affect the quality of health (Vardoulakis, Phoon, &

Ochieng, 2010).

With those main conflicts that related with the fossilized oil, new technology

discoveries have been promoted by researchers in order to overcome the dependent on

fossilized fuels. There are astonishing efforts to promote the use of solar power, hybrid

with less consumption of fuel, hydrogen fuel cell, biofuels and others to the people.

Still not many people are ready to the complete changing where the cost is still

expensive in terms of cost, not truly practical and lots more researches needed to

improvise those methods. Nevertheless, the suitable replacement and quite similar to

the fossilized fuels is the biodiesel fuels that extracted from the plants and animal fats

in term of characteristics, properties and without any modification of the engine.

In recent years, there are two main types of biofuels which refer to first of

generation biofuels called bioethanol, which is derived from starch or sugar such as

3

cane, corn and sugar beet, and second generation biofuels is biodiesel, derived from

animal fats and vegetable oils, for example from palm oil, jathropa, soy bean, rapeseed

oil, neem oil and others (Brown, 2006.). In this case, the European Union has shown

the full commitment and support for the biofuels, with targeting the demand in biofuels

for the transportation sector to 5.75% by 2010 and projected to 20% by 2020 (IEA,

2005). The Biofuels Directive issued by the European Commission in 2003 set the

target to implement the use of biofuels in EU countries and committed in achieving

their targets (European Parliament and Council Directive, 2003) and following the

proposed EU policies in 2006 to cultivate the use of biofuels massively.

Biodiesel is the generic terms for all types of fatty acid methyl ester (FAME)

which considered other organic renewable alternative fuel that can be used directly in

any mineral diesel engine with little or no modification (A. Demirbaş, 2008). They are

transesterified-vegetable oils that have been adapted to the properties of fossilized

diesel fuel and considered to be superior since they have a higher energetic yield been

combusted in the diesel engine . Current compression ignition (diesel) engines are able

to operate upon a wide range of fuels due to its specific characteristic, which is internal

combustion under a variety of operating conditions. In a world of resources, it seems

prudence to focus upon fuels, which are potentially efficient and renewable, like bio-

fuels.

Besides this advantage in fuel flexibility, compared to those of spark ignition

(petrol) engine, diesel engine can offer better engine durability, higher thermal

efficiency and more economical fuel consumption (Ayhan, 2009). Through centuries,

diesel engines were used in many sectors such as in transportation and industries.

Diesel engines usually used in heavy industries, light heavy automotive, ships,

locomotive transportation such as truck and buses, and farm machines such as

lawnmowers and tractors. The latter relates to fuel economy savings that can potentially

produce less carbon dioxide (CO2) emission. Diesel engines are therefore, part of a

long-term solution to global warming.

4

Currently, diesel engines use fossilized fuel in its combustion process.

However, it is estimated that the fossil fuel supply will decrease in the future.

Petroleum demand around the world is projected to increase by 50% by 2030 (Birol,

2010). This happens due to maximum production of the fuel, which causes fuel reserve

decreases drastically to a minimum level. Eventually it leads to demand succeed supply

and finally increase the fossil fuel price. There are a few alternatives to overcome those

problems such as the use of hybrid engine to minimize the fuel consumption and the

exhaust emission; improvement on the diesel engine with modifications such as HCCI

(Homogenous Charge Compression Ignition) engine and others. However, those

solutions are still under continuous research and not yet be produced commercially

even for hybrid.

The most preferred solution is using the renewable alternative fuels that can fuel

the diesel engine without difficulty. All biodiesels are not produced by the fossil fuel

distillation but are extracted through a chemical process called transesterification

process to produce methyl ester or ethyl ester. Those alternative fuel properties are

similar to diesel fuel but produce less emission, same or higher performance than the

diesel fuel itself (Ayhan, 2011a; M. Fatih, 2011; Nagi, Ahmed, & Nagi, 2008; Shahid

& Jamal, 2008).

1.2 OVERVIEW OF EMISSION REGULATION AND CONTROLS

Diesel engines are associated with combustion noise, engine vibration, and the

problem of nitrogen oxides (NOx)- particulate matter (PM) trade-off emissions. Table

1.1 (Appendix A1) illustrates how the European Union emission standards for heavy-

duty diesel engines have tightened since EURO I, which came into force in 1992.

Researchers have made lots of effort to reduce toxic and greenhouse gases emitted from

these engines. Several advanced technologies for clean diesel engines have been

introduced and been categorized into four strategies: (i) fuel and fuel additive, (ii) fuel

injection systems including in-cylinder technology, (iii) lubricant oil development, and

(iv) exhaust gas after-treatment devices. All these approaches have been developed into

more technology advanced levels since internal combustion (IC) engines are invented

5

with many researchers and engine manufacturers have greatly involved in improving

the technology behind the diesel engine.

1.3 PROJECT OVERVIEW

The use of renewable alternative fuels to replace the conventional fossil fuels

and its potential is well known and has been studied for many years in Asia, Europe

and United States. This is proven by the certified significant results from many

researches which are conducted and regulations and standards enforced by various

agencies. However, in Malaysia, the use of alternative fuel is still at doubtful stage due

to lack of support from the public, the government and the private sectors. This

research aims to determine the performance, combustion and emission characteristics

generated by a multi-cylinder diesel engine running on biodiesel blend, B20 with the

presence of methanol and ethanol as alcohol-based additives. The test fuels used in this

research are B100 which is palm-diesel (palm methyl ester) originated from palm oil,

B20 (20% palm-diesel mix with 80% mineral diesel), B20 alcohol-based blends with

5% by volume (B20 E5 and B20 M5) and mineral diesel as a baseline fuel for further

comparison.

In this study, there were two types of test operating modes were conducted on a

multi-cylinder diesel engine with the test fuels. Subchapter 3.3 describes those test-

operating conditions in terms to determine the engine performance, combustion and

emission characteristics for the diesel engine. Among the measured parameters

considered were engine torque, engine speed, fuel consumption, exhaust temperatures,

volumetric airflow, in-cylinder pressure and crank angle. Those data were used for

computing the calculated parameters within the engine performance included brake

power, brake specific fuel consumption (BSFC), brake thermal efficiency (BTE) and

brake mean effective pressure (BMEP). Besides, these also included the computed

combustion characteristics for instance rate of heat release (RoHR), rate of pressure rise

(RoPR), mass fraction burned (MFB), and in-cylinder gas temperature. In addition,

different level of exhaust emission formation were measured from the diesel engine

6

fuelled with the test fuels to determine which test fuel has better engine performance

with lower emission reduction.

1.4 PROBLEM STATEMENT

Most engine testing on biodiesel are commonly conducted on single cylinder

diesel engine, which determines engine performance and emission characteristics. This

provides a better understanding on how well the single cylinder diesel engine operates

with the biodiesel. However, single cylinder diesel engines are designed mostly for the

agricultural purposes but not in the transportation sectors. Insufficient information on

biodiesel operates with multi-cylinder diesel engine has motivated to determine the

research gaps that could incorporate through this study. In addition, the use of biodiesel

operates with multi-cylinder diesel engine is not a popular method due to its higher fuel

consumption when engine testing is conducted. Furthermore, it requires appropriate

testing apparatus include larger capacity dynamometer and sophisticated

instrumentation system. Because of that reasons, some research gaps have been

considered in terms to construct the need of this study. Research gaps in this study are

outlined as:

i. Palm-diesel blend, B20 used as the main subject for the study.

ii. Palm-diesel blend, B20 dilutes with alcohol additives, ethanol and

methanol in 5% by volume, designated as B20 E5 and B20 M5.

iii. The use of a multi-cylinder diesel engine operates with mineral diesel as

a baseline fuel, B100 (palm-diesel), B20 and its alcohol blends (B20 E5

and B20 M5).

1.5 OBJECTIVE OF THE STUDY

To determine the engine performance, combustion and exhaust emission

characteristics of mineral diesel, B100 (palm-diesel), B20, B20 E5 and B20 M5 which

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are palm-diesel blend fuels with ethanol and methanol as alcohol fuel additives in a

compression ignition (CI) engine.

1.6 SCOPE OF THE STUDY

i. Literature reviews on application of biodiesel and the practical use of

fuel additives in engine testing

ii. Develop and commission an engine test cell facility fully equipped with

the instrumentation system.

iii. Evaluate the psychochemical properties of mineral diesel, B100 (palm-

diesel), B20, B20 E5 and B20 M5.

iv. Conduct the engine testing at the increasing engine speeds from 1500

rpm to 3500 rpm with a constant partial throttle position on the multi-

cylinder diesel engine fueled with the test fuels to determine engine

performance, combustion characteristics and exhaust emission.

v. Conduct the engine testing at three different engine loads, 0.05 MPa, 0.4

MPa and 0.7 MPa with a constant engine speed of 2500 rpm on the

multi-cylinder diesel engine fueled with the test fuels to determine

engine performance, combustion characteristics and exhaust emission.

vi. Evaluate the engine performance, combustion and exhaust emission

characteristics on the multi-cylinder diesel engine operated with the test

fuels.

1.7 RESEARCH METHODOLOGY

The research starts with literature studies on mineral diesel and biodiesel

especially palm-diesel. In this study, literature reviews focus to the engine performance,

combustion and exhaust emission characteristics of the biodiesel and biodiesel-alcohol

blend fuels; running on a single cylinder and multi-cylinder diesel engines. Literature

reviews also cover the psychochemical properties of the biodiesel and biodiesel-alcohol

blend fuels include density, flash point, pour point, Cetane number and other properties.

The use of alcohol as additives in the diesel and biodiesel blend fuels is covered in the

next literature review.

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In the experimental set up, the research has been divided into two sections

where one section is provided for the fuel analysis. Suitable methods and apparatus

have been assigned for the fuel analysis according to the current standard. While the

other section focuses on the engine test rig set up, this includes the measurement and

analysis of the engine performance, combustion characteristics and exhaust emissions.

The engine test rig set up follows the standard of SAE J1349 - Engine Power Test

Code—Spark Ignition and Compression Ignition—Net Power Rating as well as SAE

J1312 - Procedure for Mapping Performance—Spark Ignition and Compression

Ignition Engines to meet the requirement for the standard engine testing. Parameters

such as ambient temperature, inlet air supply pressure and temperature, fuel

temperature at fuel tubing, oil sump pressure and temperature, exhaust temperature

have also been measured and recorded in the engine test rig. The measured data used to

compute the observed brake power, corrected brake power, corrected BMEP, mass air

flow, volumetric fuel flow rate, brake specific fuel consumption (BSFC) and brake

thermal efficiency (BTE).

A Mitsubishi four-cylinder, four stroke water-cooled diesel engine has been

coupled to a 150 kW eddy current dynamometer to conduct the fuel testing in this study.

It has been incorporated with a DEWE-800 DAQ system from DEWETRON to

measure, record and analyse the results include exhaust temperatures, in-cylinder

pressure and crank angle degree (CAD) during the engine testing. In addition, two

types of test operating modes have been performed on the current multi-cylinder diesel

engine fuelled with mineral diesel, B100 (palm-diesel), B20, B20 E5 and B20 M5

blend fuels. The results mainly consist of engine performance, combustion and exhaust

emission characteristics. Furthermore, as for the requirements in the fuel testing, the

chemical properties for fuels and additives have been determined using chemical lab

apparatus following stringent procedure by the ASTM standards.