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FMC Fuel, Mixture Formation and Combustion Process, Vol. 4 No. 1 (2022) p. 1-5

Fuel, Mixture Formation and Combustion Process

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e-ISSN: 2672-7331

Characterization of Physical Properties for Diesel-alcohol and
Biodiesel-alcohol Blends

Mohd Hafizil Mat Yasin1,a*, Mohd Rosdi Salleh1,b, Mohd Hafiz Ali2,c, Rizalman Mamat3,d

1Automotive Technology Center (ATeC),
Politeknik Sultan Mizan Zainal Abidin, Dungun, 23000, MALAYSIA

2Department of Petrochemical Engineering,
Politeknik Tun Syed Nasir, Pagoh, 84600, MALAYSIA

3Centre of Exellence for Advanced Research in Fluid Flow (CARIFF),
Universiti Malaysia Pahang, Pekan, 26600, MALAYSIA

*Corresponding Author

Email: [email protected], [email protected], [email protected], [email protected]

Received 20 February 2022; Abstract:
Accepted 21 March 2022; Alternatives to conventional fossilized fuels include biodiesel and its alcohol blend fuels. The
Available online 10 May 2022 physical properties of the fuel are one of the most significant aspects in assessing its
efficiency. Strict protocols are used in observation and calculation to describe the actual
properties of biodiesel and its alcohol blend fuels to obtain the density, viscosity, Cetane
number (CN), flash point, and energy content quantity. These discovered properties are
beneficial in every arithmetical simulation for further research. Therefore, these fuel
characteristics are beneficial to explain how the engine works with certain fuels in terms of
efficiency, combustion, and emission characteristics. The study of biodiesel and its alcohol
mix fuels was carried out in the UMP Chemical laboratory to determine the fuel properties
using several analytical instruments such as a KEM portable density/specific gravity meter,
KV1000 Koehler Digital constant temperature kinematic viscosity bath, Shatox Cetane
Number SX-300, Pensky-Martens closed tester and a Parr B41 calorimeter with an oxygen
combustion bomb. Mineral diesel, palm biodiesel (PBD), diesel-alcohol (DBu10, DE10), and
biodiesel-alcohol (BBu10, BE10) blends of 10% butanol and ethanol were compared in terms
of properties. When mixing biodiesel with mineral diesel, the inclusion of butanol and ethanol
allows reducing the viscosity and density of the biodiesel concentration. A significant rise in
Cetane number due to increased alcohol content in biodiesel blend fuels compared to PDB.
Biodiesel and its alcohol blends, on the other hand, satisfy the EN14214 requirements.

Keywords: physical properties, palm biodiesel, alcohol blends, butanol, ethanol

1. Introduction Furthermore, several authors have contrasted the efficiency of
conventional diesel engines operating on biodiesel and their
Biodiesel is an alkyl monoester made from vegetable or blends with mineral diesel containing alcohol as an additive [6–
waste cooking oils and animal fats[1–3]. It was produced using 8]. Viscosity is the calculation of internal friction or the
a transesterification procedure that involved the use of reluctance of oil to flow smoothly. Biodiesel has a slightly
methanol as a catalyst. Biodiesel is specified in the European higher viscosity than mineral fuel, but it's around the same as
Union and the United States by EN14214 and ASTM 6751-02. pure vegetable oils. A transesterification process will greatly
These standards govern biodiesel to ensure that it meets the reduce the viscosity of gasoline. Low temperatures make
required standards during the fuel production process by viscosity more important, as it prevents fuel from flowing
reducing glycerin, catalyst, and alcohol to the bare minimum. smoothly from the storage tank to the engine. The higher
In addition, the transesterification process is used to strip viscosity will be resulting in lower atomization of the fuel spray
unwanted constituents from the crude, such as soil and water. and inaccuracy in the application of fuel injectors.
Biodiesel has been proved as a replacement for mineral diesel
while still reducing emissions substantially, according to Furthermore, fuel density is known as the weight of a unit
studies undertaken by various researchers around the world volume of fuel. The minimum density value is desired to
[4,5]. In the latest trend, concentrations such as alcohol have achieve optimum engine strength through the injection pump's
been diluted with biodiesel to reach similar targets. fuel flow control. It also necessitated minimizing smoke output

*Corresponding author: [email protected]
2022 FAZ Publishing. All right reserved.

Mohd Hafizil, MY. et al., Fuel, Mixture Formation and Combustion Process, Vol. 4 No. 1 (2022) p. 1-5

while operating at full power. The amount of potassium (a) (b)
hydroxide (KOH) required to neutralize free fatty acids (FFAs)
in 1 gramme of oil is known as the acid value number in (c) (d)
milligrams. It can be used as a vegetable oil consistency
measure to monitor the oil's deterioration over time. The (e)
maximal value of an acid number, according to ASTM D6751, Fig. 3 - Analytical instruments used to measure fuel
is 0.5 mgKOH/g. The Cetane number (CN) is a measure of the properties; (a) KEM Portable Density/Specific Gravity
fuel's ignition efficiency. During the combustion cycle, it Meter [DA-130N] (ASTM D4052); (b) KV1000 Koehler
determines if the fuel has a longer or shorter ignition delay. The Digital constant Temperature Kinematic Viscosity Bath
carbon chain length lengthens, resulting in an increase in (ASTM D445; (c) Shatox Cetane Number SX-300 (ASTM
Cetane number. Standard diesel engines tolerate it between 40 D613); (d) Pensky-Martens Closed Tester (Flash Point)
and 55 cetane, although below 38 induces a faster rise in (ASTM D93); (e) A Parr B41 calorimeter with an Oxygen
ignition delay. In contrast to mineral diesel and biodiesel,
alcohol has a lower Cetane number. Engine noise and longer Combustion Bomb and a Model 6772 Digital
ignition delay are two consequences that could arise when Thermometer (ASTM D240)
using a fuel with a lower Cetane number. Clean alcohols have
a low cetane number (8 for ethanol and 3 for methanol), making The blending process was conducted using a 220V digital
them weak compression ignition engine fuels. In addition, the rotary mixer and a 1 liter glass beaker, as depicted in Figure 2.
cetane amount of diesel-alcohol blend fuel is affected by the The mixing process for all blended fuel was stirred for 20
content of the base diesel, the level of alcohol in the blend, and minutes at 200 rpm then continued for a second time at the same
the addition of cetane improver additives. The aim of the study condition. Another 30 minutes of stirring process was
is to determine the fuel properties of palm biodiesel (PBD), performed to ensure the homogeneity of the blended fuels.
diesel-alcohol (DBu10, DE10) and biodiesel-alcohol (BBu10, Figure 3 portrays various analytical apparatus for assessing fuel
BE10) blends of 10% v/v butanol and ethanol with mineral properties. Many of the research methods follow the strict
diesel as a baseline fuel. ASTM protocols that manufacturers prescribe. To ensure that
the findings were not affected by environmental errors, the
2. Methods and Preparations experiments were carried out in a regulated room temperature,
pressure, and relative humidity.
Mineral diesel (D), palm biodiesel (PBD), DBu10 (90%
mineral diesel with butanol 10% blend), DE10 (90% mineral 3. Finding and Analysis
diesel with ethanol 10% blend), BBu10 (palm biodiesel 90% Experiments on fuel properties yielded the following
with butanol 10% blend), and BE10 (palm biodiesel 90% with
ethanol 10% blend) as shown in Figure 1. findings in Table 1. The tests were carried out five times and
meticulously reported on the digital device. The abundance of
DB0 PBB10D0 BBBBUu1010 DDBBUu110 0 BBEE110 0 DDEE1100 biodiesel and alcohol in the blend fuels has a major effect on
the fuel properties, as seen in the table. As opposed to mineral
Fig. 1 - Types of fuel

220V Digital Blending time
rotary mixer
20 minutes (200
Stirred fuel rpm)

+

20 minutes (200
rpm)

+

30 minutes

Beaker

Fig. 2 - Blending procedure

2

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Fuel, Mixture Formation and Combustion Process Vol. 4 No. 1 (2022) p. 1-5

diesel, biodiesel and its alcohol mix fuels have distinct

characteristics.
Table 1 – Fuel properties

Types of fuel
Properties

D PBD DBu10BBu10 DE10 BE10

Density
(g/cm³) 0.83 0.8671 0.8236 0.8583 0.8226 0.8619

@25°C

Viscosity 5.1 7.495 3.576 6.026 3.674 4.311
(mm²/s) )cS

tC)etane 47.8 52.8 51 52.4 43.82 55.5
number

Flash point 60 80 56.4 74.4 55.2 73.2 Fig. 5 - Viscosity of mineral diesel (D), palm biodiesel
(°C) (PBD) and alcohol blends

Energy The viscosity of the fuel was calculated in a viscosity bath in
Content 44.8 38.6 43.57 37.99 43 37.42 the Chemical Laboratory, as seen in Figure 5. It explicitly
(MJ/kg) reveals that mineral diesel is 31.4 percent different from PBD.
This is due to the abundance of free fatty acids (FFA) in
biodiesel [11]. Furthermore, the transesterification process,
which transforms vegetable oils into biodiesel, significantly
reduces the fluid's viscosity. DBu10 has the lowest viscosity,
with a value of 3.576 mm2/s. As a result of the increased
biodiesel concentration, the viscosity of the blends will
increase. In contrast, the viscosity of DBu10 and BBu10 differs
by 40.7 percent.
The limited amount of alcohol dilution in biodiesel blends, on
the other hand, has been shown to decrease the viscosity of the
fuel. The flash point of PBD when diluted with 10% by volume
of butanol and ethanol, respectively, can be seen in the figure.

Fig. 4 - Density of mineral diesel (D), palm biodiesel (PBD) Fig. 6 - Cetane number (CN) of mineral diesel (D), palm
and alcohol blends biodiesel (PBD) and alcohol blends

The density of mineral diesel, palm biodiesel (PBD), Biodiesel has a significantly higher Cetane number (CN)
diesel-alcohol and biodiesel-alcohol blends used in the analysis than mineral diesel [12]. Figure 6 depicts the individual CN of
is shown in Figure 4. The density of the PBD is considered to the tested fuels. As shown in the graph, mineral diesel has the
be the highest at 0.8671 g/cm3, while the density of mineral lowest CN at 47.874, while BE10 has the highest at 55.5. The
diesel is the lowest at 0.8264 g/cm3 as discovered by other CN increases as the percentage of biodiesel in the blend
researchers [9]. The elimination of glycerol from PBD has increases. This is due to the fact that the Cetane content of
resulted in 1.01 percent and 0.6 reductions in the densities of biodiesel is determined by the fatty acid distribution in the
BBu10 and BE10. It is obvious that increasing the biodiesel initial oil or fat. The longer the fatty acid carbon chains are and
content in the fuel blend would increase the fuel's density.
Mineral diesel and biodiesel have very close densities,
according to Moraes et al., 2008, although it should be noted
that the density of biodiesel is influenced by the raw material
(feedstock) used in its processing.

3

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Mohd Hafizil, MY. et al., Fuel, Mixture Formation and Combustion Process, Vol. 4 No. 1 (2022) p. 1-5

the more saturated the molecules are, the higher the Cetane content of 37.99 MJ/kg, which is 12.8 percent lower than
number [13]. DBu10's 43.57 MJ/kg. The energy content for BE10, on the
other hand, is the lowest at 37.42 MJ/kg. As compared to
Fig. 7 - Flash point of mineral diesel (D), palm biodiesel mineral diesel, PBD has been shown to degrade rapidly over
(PBD) and alcohol blends long periods of time.

The flash point of the fuels determined by the Pensky-Martens 4. Conclusion
closed tester is seen in Figure 7. (refer to Figure 3d). The flash
point of PBD when diluted with 10% by volume of butanol and The study on fuel properties for diesel-alcohol and
ethanol, respectively, can be seen in the graph. The flash point biodiesel-alcohol blend fuels when being compared with
of PBD differs by 25 percent from mineral diesel and 29-31 mineral diesel have been concluded into points as followed:
percent from diesel-alcohol blend fuels, as seen in the figure. i. A 10% addition of butanol and ethanol concentrations has
That is to say, the biodiesel in this situation is unlikely to
combust due to its higher flash point. When alcohol additives dramatically reduced the density and viscosity of the
10 percent by volume are diluted into biodiesel the flash points biodiesel-alcohol blends.
for such biodiesel-alcohol blends are lower than PBD. The ii. A small concentration of butanol and ethanol, 10% by
biodiesel-alcohol blends have an average flash point of 55 to volume diluted in diesel-alcohol blends, significantly
56 degrees Celsius. In this case, the flash points were measured reduced the blends' flash point and energy content.
as a function of percentage of biodiesel, the results determined However, as a result, the cetane number for DBu10 is
that the flash points decrease as the percentage of biodiesel increased and on the other hand, a significant decrease of
decreases for the blends with the 10 percent addition of butanol Cetane number (CN) is found on DE10.
and ethanol. iii. Some fuel properties, including density, viscosity, Cetane
number, energy content and flash point have significant
Fig. 8 - Energy content of mineral diesel (D), palm differences for various alcohol concentrations other than
biodiesel (PBD) and alcohol blends butanol and ethanol.

Mineral diesel proved to consist of a higher heating value, as Acknowledgement
documented by Amin et al., 2016. The energy content for the
measured fuels is shown in Figure 8. The energy content for Universiti Malaysia Pahang is greatly acknowledged for
mineral diesel is the highest, at 44.8 MJ/kg, as can be seen in the technical and financial supports under UMP Short grant
Table 1. BBu10, on the other hand, has a slightly lower energy (RDU100334).

4 References
[1] Azadbakht M, Safieddin Ardebili S, Rahmani M. (2021).
Published by FAZ Publishing
http://www.fazpublishing.com/fmc A study on biodiesel production using agricultural wastes
and animal fats. Biomass Convers Biorefinery, 2021:1–
7.
[2] Ortiz Lechuga EG, Rodríguez Zúñiga M, Arévalo Niño
K. (2020). Efficiency Evaluation on the Influence of
Washing Methods for Biodiesel Produced from High
Free Fatty Acid Waste Vegetable Oils through Selected
Quality Parameters. Energies, 2020;13.
[3] Rajak U, Verma TN. (2018). Effect of emission from
ethylic biodiesel of edible and non-edible vegetable oil,
animal fats, waste oil and alcohol in CI engine. Energy
Conversion & Management, 166:704–18.
[4] Tayari S, Abedi R, Rahi A. (2020). Comparative
assessment of engine performance and emissions fueled
with three different biodiesel generations. Renewable
Energy, 147:1058–69.
[5] Mofijur M, Rasul M, Hassan NMS, Uddin MN. (2019).
Investigation of exhaust emissions from a stationary
diesel engine fuelled with biodiesel. Energy Procedia,
160:791–7.
[6] Rathinam S, Balan KN, Subbiah G, Sajin JB, Devarajan
Y. (2019). Emission study of a diesel engine fueled with
higher alcohol-biodiesel blended fuels. International
Journal Green Energy, 16:667–73.
[7] Ağbulut Ü, Sarıdemir S, Albayrak S. (2019).
Experimental investigation of combustion, performance
and emission characteristics of a diesel engine fuelled
with diesel–biodiesel–alcohol blends. Journal Brazilian
Soc Mechanical Science Engineering, 41:389.
[8] Ma Q, Zhang Q, Liang J, Yang C. (2021). The
performance and emissions characteristics of
diesel/biodiesel/alcohol blends in a diesel engine. Energy
Reports, 7:1016–24.
[9] Bari S, Hossain SN. (2019). Performance and emission

Fuel, Mixture Formation and Combustion Process Vol. 4 No. 1 (2022) p. 1-5
analysis of a diesel engine running on palm oil diesel
(POD). Energy Procedia, 160:92–9.
[10] Moraes MSA, Krause LC, da Cunha ME, Faccini CS, de
Menezes EW, Veses RC. (2008). Tallow Biodiesel:
Properties Evaluation and Consumption Tests in a Diesel
Engine. Energy & Fuels, 22:1949–54.
[11] Sahar, Sadaf S, Iqbal J, Ullah I, Bhatti HN, Nouren S.
(2018). Biodiesel production from waste cooking oil: An
efficient technique to convert waste into biodiesel.
Sustainable Cities and Society, 41:220–6.
[12] Simsek S. (2020). Effects of biodiesel obtained from
Canola, sefflower oils and waste oils on the engine
performance and exhaust emissions. Fuel, 265:117026.
[13] Folayan AJ, Anawe PAL, Aladejare AE, Ayeni AO.
(2019). Experimental investigation of the effect of fatty
acids configuration, chain length, branching and degree
of unsaturation on biodiesel fuel properties obtained from
lauric oils, high-oleic and high-linoleic vegetable oil
biomass. Energy Reports, 5:793–806.

5

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Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with
2-butyl Alcohol/ Diesel Blends at Different Speed

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Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

Combustion Characteristics of Direct Injection (DI) Diesel
Engine Fueled with 2-butyl Alcohol/ Diesel Blends at
Different Speed

Akasyah Mohd Khathri, Mohd Rosdi Salleh
Politeknik Sultan Mizan Zainal Abidin

[email protected], [email protected]

Rizalman Mamat
Universiti Malaysia Pahang

[email protected]

Abstract

Alcohol is one of the alternative fuels that can give significant different on engine
combustion characteristic as well as exhausts emission. In this study, the influence of 2-
butyl alcohol/ Diesel blends on the combustion characteristic of a DI diesel engine was
investigated by using three different fuel blends (Diesel, DBu5, and DBu10). Both 2-butyl
alcohol and diesel fuel were blended together before tested on 3 liter common-rail direct
injection diesel engine by their percentage (volume) of 2-butyl alcohol 5% (DBu5) and 2-
butyl alcohol 10% (DBu10). The test results were analysed and compared with a base diesel
engine operate at same speed and load. The tests in a compression ignition engine
including analysis of combustion characteristics. The experiments were handled at five
different speeds in the same operating condition. The results shows that the use of 2-butyl
alcohol fuels blends, ignition delay is increased, maximum in-cylinder pressures are
marginally reduced and in-cylinder temperatures are reduced during the combustion. The
addition of 2-butyl alcohol can considerably improve CO2 emissions and slightly increase on
NOx and CO.

Key Words: 2-butyl alcohol, DI diesel engine, Combustion characteristics

Introduction

This modern era, the use of engine technology is growing rapidly.
Diesel engine is capable of reducing NOx production rates with an excellent
fuel economy. Diesel engines usually provide fuel savings of 25 to 30%
better than the same gasoline engine and about 15 to 25% better than
hybrid-powered cars (Balat & Balat, 2008).

Alcohol is considered as a potential biofuel for road vehicle in near
future (Doğan, 2011; D. C. Rakopoulos et al., 2010; Szulczyk, 2010; Yilmaz
et al., 2014; Zhang & Balasubramanian, 2014). 2-butyl alcohol (also known
2-Butanol) mainly produces from agricultural feedstock such as sugar cane,
potato and corn (Doğan, 2011). Butanol is produce through a fermentation
process. During this process, acetic acid and glycols are formed. The
Butanol is subsequently isolated after fermentation by using adsorption and
distillation techniques. Butanol is an excellent fuel for compression ignition
(CI) engines (Çay et al., 2013). Butanol has lower heating value, a higher
cetane number, larger viscosity, lower volatility, a higher flashpoint and
better lubricity. In addition, diesel fuel can be mixed with butanol without

1

Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

critical phase separation in certain time. Butanol molecules contain
hydroxyl and alkyl, that easier to merged into diesel fuel. In fact, butanol
has very good inter-solubility with diesel fuel without any surfactant (Yao et
al., 2010).The Butanol has four main isomer. Every isomer has different
melting and boiling points. Iso-butanol and n-Butanol have limited
solubility, while sec-butanol has substantially greater solubility. Tert-
butanol is fully miscible with water. By owing these advantages, butanol–
diesel fuel blends studies began to increase in the recent years (Doğan,
2011; D. C. Rakopoulos et al., 2011; Yao et al., 2010; Yoshimoto et al.,
2013). These characteristics show that butanol has the potential to
overcome low-carbon alcohol problems. Furthermore, the great potential is
to use Butanol in diesel engine to reduce the dependency of diesel engine to
petroleum diesel.

In this work, for the 2-butyl alcohol-diesel blends, a combustion
analysis is performed for studying the relevant combustion behaviour from
other researcher. The experimental cylinder pressure from the kistler crank
angle encoder placed at engine, are directly processed in connection with
Dewetron system. The combustion results combined with the differing
physical and chemical properties of the 2-butyl alcohol against those for the
diesel fuel, which constitutes the ‘baseline’ fuel, aid the correct
interpretation of the observed engine behavior combustion wise when
running with this 2-butyl alcohol-diesel blend.

Material And Methodology
Experimental setup

The experimental setup consists of an Isuzu 4JJ1 turbocharger, four
cylinder diesel engines as engine test bed and a data acquisition system in
control room. This engine is equipped with an exhaust gas recirculation
system; however, in this study the EGR mode is set to off. The schematic of
the experimental setup is shown in Figure 1 and specification of the test
engine was given in the Table 1. A 150kW ECB-200F SR No. 617 from
Dynalec Controls eddy-current dynamometer was used in the experiments.
A universal propeller shaft was used to transfer the energy from the engine
to the dynamometer. The dynamometer brake and the operating conditions
of the engine are characterized by the speed and torque. The control system
of the dynamometer has been mounted in the control room. The engine
speed can be controlled at the desired value. Brake torque is measured by
the eddy current dynamometer and it value was displayed through a
Dynalec dynamometer controller and DeweCA system. The function of
dynamometer is to absorb the power electromechanically and delivered by
the engine. The heat generated by the applied torque has been removed by
utilizing the external cooling tower. Engine Power Test Code for Compression
Ignition SAE J1349 was used as standard for testing the engine (SAE, 2004).

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Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed
Fuel tank

Dyno cooling tower Engine water cooler

Exhaust 150 kW
system Dynamometer

Air intake
system

Engine Fuel flow meter

Engine room

Gas analyser

Dyno control Combustion Temperature
panel data data

Data acquisition system Control room

Figure 1: Schematic diagram of the experimental setup

The Isuzu 4JJ1 engine as shows on Table 1 was used in this experiment.
The engine was tested at different loads and engine speeds (1000 rpm to
3000 rpm) using different percentage of Diesel with 2-butyl alcohol (5% and
10%) blends at half load. Researchers summarized the DBu5 (Diesel - 2-
butyl alcohol 5 %) and DBu10 (Diesel – 2-butyl alcohol 10 %). At the
beginning of each test, the throttle position was adjusted to give a speed of
1000 rpm at a lowest dynamometer load. In the experiments, the load was
increased slowly as the engine speed increase by 500 rpm up to 3000 rpm.
For each engine speed, the load is constant at 50% while the fuel
consumption rate was recorded. The engine was started with the original
diesel fuel first and left to warm up for about 25 to 30 min, and then the
diesel-2-butyl alcohol blend was gradually introduced. At the end of each
test, the engine was run using original diesel fuel for about 30 to 45 min in
order to flush the fueling system from any diesel-2-butyl alcohol blended
residues.

Table 1: Specification of the engine

Engine Parameters Value
Model
Isuzu 4JJ1
Bore (mm) (Turbocharged)
Stroke (mm)
Displacement (L) 95.4
Number of cylinders 104.9
Compression ratio 2.999 L
4 in-line
17.5

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Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

Fuel preparation

Table 2: Properties of diesel fuel and 2-butyl alcohol

Fuel Properties Unit Measurement Diesel 2-butyl
fuel alcohol
Density at 20°C kg/m3 ASTM D4052 837
Cetane number - ASTM D613 50 810
Kinematic Viscosity at ASTM D445 25
40°C mm2/s 2.6
Lower Heating Value ASTM D240 3.6
Specific heat capacity MJ/kg ASTM D2766 43.25
Flash point J/kg°C 1850 33.1
Oxygen ASTM D93 2545
Boiling point °C 52
%weight 0 35
21.6
°C 102

Results calculation method
The basic heat release rate calculation was extended by Krieger and

Borman (Krieger & Borman, 1966) to obtain an apparent fuel mass burning
rate. Many other researchers have also investigated and extended the work
related to heat release rate calculations. Simple method of analysis which
yields the rate of heat release of the fuel’s chemical energy (heat release)
through the diesel engine combustion process is governed by basic
assumptions and also from the first law of thermodynamics. These
assumptions state that the trapped charge behaves as an ideal gas

contained in a uniform single zone of constant composition from the intake
valve closing to the exhaust valve opening and the energy released by
combustion can be modelled as a heat addition to the cylinder. Based on
these assumptions the rate of heat release is calculated as a function of the
cylinder pressure and temperature at certain crank angle degree using the
first law of thermodynamics. Heat release analysis computes how much heat
would need to have been added to the cylinder contents, in order to produce
the observed pressure variations. From the first law of thermodynamics the
following equation is used (Heywood, 1988)

= 1 + 1 1 (1)
− −

Results And Discussion
Results are discussed base on the new information of blended fuel

experimented on the engine combustion characteristics, also from creative

results of the blend combustion in the diesel engine or more detailed

emissions reduction benefits compared to the other researches for diesel–2-
butyl alcohol blends.

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Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

In-cylinder Pressure
The several of pressure inside the cylinder with respect to the crank

angle degree for fuel-blends; in comparison with diesel fuel at different
engine operating is revealed in Figure 2. Essentially, it shows that the in-
cylinder pressure is increased with the increasing of engine load as well as
advance of injection timing and peak cylinder pressure come off well along
in terms of the crank angle for blends at low loads.

Figure 2 depicts the traces of maximum in-cylinder pressure of
conventional diesel blended fuel DBu5, and DBu10 using the average of 100
consecutive cycles to reduce the engine cyclic variation effects. It is obvious
that, at the same engine operating conditions, there is a slight difference
during the combustion stroke. The peak pressure has reached up to 86.3
bar at 10 deg. ATDC and 3000 rpm for the DBu10, while it is raised to 83.6
bar at 9 deg ATDC and 3000 rpm for base diesel. The difference in peak
pressure rise (4%) is due to the high oxygen content and specific heat
capacity of blended fuel contains 2-butyl alcohol. This statement support by
(Kumar et al., 2013), that butanol had a higher normalized peak pressure,
indicating that 2-butyl alcohol had higher potential thermal efficiency. All
maximum peak pressure achieved at high speed. These results are in
agreement with those from a previous study (Jin et al., 2011; Kumar et al.,
2013; Liu et al., 2014; Yusri et al., 2016) which finds an increase in the
maximum in-cylinder pressure with the increasing blending ratio of alcohol
blended fuel compared to the base diesel.

Injection timing also significantly affects engine performance as well
as exhaust emissions. A trend is observed from the figure 2c that with
increasing 2-butyl alcohol fraction, the start of combustion is delayed, the
combustion phasing is retarded, and the peak HRR (figure 3c) increases up
to 45% of DBu10. This was due to lower cetane number and higher specific
heat capacity of 2-butyl alcohol extended the diesel ignition delay period.

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Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

Figure 2: In-cylinder pressure at half Load

Heat release rate
The heat release is used to calculate how much heat will be required

to add the contents of the cylinder, to generate pressure variation observed.
The heat release rate is calculated from in-cylinder combustion aimed to
investigate the combustion characteristics of the diesel engine and the fuel
used (Heywood, 1988; Pulkrabek, 2004). The process of direct injection
combustion diesel engine that modern can be divided into two phases. The
first phase is the phase of the premix and begins after the start of injection
where fuel is mixed with air and form a fuel rich burn zone during the
ignition delay period. After ignition, premixed mixture quickly responds. The
second phase begins when oxygen is depleted, at which combustion is
changed to mode dispersion, which contains emissions at high
temperatures.

Figure 3 shows the rates of heat release for different blends speed and
load condition. The curve shows the heat release rates of various fuels at
different speed. It was observed blended fuel produced a bit higher in heat
release compare to diesel especially at higher speed. It can be found that the
maximum rate of heat release in blended fuel higher than base diesel, but
the pattern shows a comparable characteristic to that of diesel fuel. The
premixed combustion heat release increases slightly with proportion of 2-
butyl alcohol contents due to lower cetane number (Hulwan & Joshi, 2011).
Higher premixed heat release rate on DBu5 and DBu10 promoted better air-
fuel mixing process while slightly slower ignitions delay. Greater 2-butyl

6

Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

alcohol portion in the blend indeed results higher in premixed combustion
rate of heat release. As discussed above, this is due to the enhanced mixing
process and extended ignition delay caused by the addition of 2-butyl
alcohol.

The maximum rate of heat release is delayed as 2-butyl alcohol additive
increases in the blend. Furthermore, the maximum rate of heat release is
reduced to below that of the diesel fuel for all 2-butyl alcohol ratios at low
speed. The rate of heat release is significantly delayed for 10% 2-butyl
alcohol additive with higher value of maximum rate of heat release of 1970
J/deg. at 3 deg ATDC on 3000 rpm due to the retard in the ignition timing.
Furthermore, the maximum rate of heat release for blended fuel with 10% 2-
butyl alcohol is slightly higher than that of base diesel at the same crank
angle retard.

Figure 3: Heat release rate at 50% Load 7

Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

In-cylinder gas temperatures
The mean cylinder gas temperature can be calculated based on the in-

cylinder pressure for each crank angle degree by considering the ideal gas
assumptions with a known gas temperature at reference location such as
inlet gas closure. During the combustion process the in-cylinder pressure
and temperature are changed simultaneously. The fuel oxygen content
directly affects the combustion process and the trends of the cylinder gas
temperature.

Figure 4 demonstrates the cylinder gas temperatures against the
crank angle degree for diesel, DBu5 and DBu10 at various engine speeds.
The fuel combustion behaviour after the peak pressure is more comparable
to mineral diesel fuel. Overall, there are sudden increases in temperature
tendency between -4° to 6° CAD depend on their speed. The cylinder gas
temperature of blended fuel is lower that of the diesel fuel for low speed but
higher at high speed. This is due to late injection leads to lower cylinder
temperatures. The benefit is, there is no time available for oxidation of the
emission or soot particles before opening of the exhaust valve.

8

Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

Figure 4: In-cylinder gas temperatures at 50% Load

Conclusion
Generally 2-butyl alcohol addition, in adequate quantity, in the blends of

diesel, drastically improved the combustion of diesel fuel at low and middle
speed. Oxygen content in 2-butyl alcohol increased up to 21.6% by means of
weight ensuring the optimum combustion in the cylinder. The maximum
peak pressure has reached up to 86.3 bar at 10 deg. ATDC, 3000 rpm for
the DBu10, 83.7 bar for DBu5 while base diesel has 83.6 bar at 9 deg.
ATDC, 3000 rpm. This difference in the peak pressure rise (4%) is due to the
high oxygen content and specific heat capacities of blended fuel content 2-
butyl alcohol in DBu10. The rate of heat release is significantly delayed for
10% 2-butyl alcohol additive (DBu10) due to the retard in the ignition
timing. The addition of 2-butyl alcohol can considerably improve CO2
emissions and slightly increase on NOx.

Aknowledgement
The authors would like to thanks University Malaysia Pahang for

providing facilities and funding during the course of this study

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Heywood, J. (1988). Internal combustion engine fundamentals. New York:
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Hulwan, D. B., & Joshi, S. V. (2011). Performance, emission and

combustion characteristic of a multicylinder DI diesel engine running

9

Politeknik & Kolej Komuniti Journal of Engineering and Technology, Special Issues on CoT 2018
eISSN 0128-2883

Combustion Characteristics of Direct Injection (DI) Diesel Engine Fueled with 2-butyl alcohol/ Diesel Blends at Different Speed

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production and application of n-butanol as a biofuel. Renewable and

Sustainable Energy Reviews, 15(8), 4080-4106.

doi:http://dx.doi.org/10.1016/j.rser.2011.06.001

Krieger, R. B., & Borman, G. L. (1966). The Computation of Apparent Heat

Release for Internal Combustion Engines. ASME paper, 66.

Kumar, S., Cho, J. H., Park, J., & Moon, I. (2013). Advances in diesel–

alcohol blends and their effects on the performance and emissions of

diesel engines. Renewable and Sustainable Energy Reviews, 22, 46-

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Combustion and emissions characteristics of a compression ignition engine
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3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

Combustion and emissions characteristics of a compression
ignition engine fueled with n-butanol blends

I M Yusri1, R Mamat1, O M Ali1, A Aziz1, M K Akasyah1, M K Kamarulzaman1,
C K Ihsan1, H M Mahmadul1, and S M Rosdi1
1Faculty of Mechanical Engineering, Automotive Engineering Centre
Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia

Email: [email protected]

Abstract. The use of biomass based renewable fuel, n-butanol blends for compression ignition
(CI) engine has attracted wide attention due to its superior properties such as better miscibility,
higher energy content, and cetane number. In this present study the use of n-butanol 10%
blends (Bu10) with diesel fuel has been tested using 4-cylinder, 4-stroke common rail direct
injection CI engine to investigate the combustion and emissions of the blended fuels. Based on
the tested engine at BMEP=3.5Bar Bu10 fuel indicates lower first and second peak pressure by
5.4% and 2.4% for engine speed 1000rpm and 4.4% and 2.1% for engine speed 2500rpm
compared to diesel fuel respectively. Percentage reduction relative to diesel fuel at engine
speeds 1000rpm and 2500rpm for Bu10: Exhaust temperature was 7.5% and 5.2% respectively;
Nitrogen oxides (NOx) 73.4% and 11.3% respectively.

1. Introduction
Compression Ignition (CI) engine is a well-known internal combustion engine available in the present
day. Generally CI engine is producing higher thermal efficiency compared to spark ignition (SI)
engine because of higher compression ratio of the engine and the carbon content of the fuel itself [1].
Unfortunately the pollution emitted by the CI engine usually producing higher nitrogen oxides (NOx)
and soot. In order to meet the stringent emissions regulations, increasing energy demand and depletion
of non-renewable fuels the present worldwide research is directed to search for alternatives fuel;
alcohol and biodiesel for CI engine.

Alcohol fuels such as methanol (CH3OH), ethanol (C2H5OH), and butanol (C4H9OH) can be used
with diesel fuels in various percentage blends for CI engine as a clean alternative fuel source. Low
percentages of alcohol; 5%, 10% and 15% in diesel fuel blends does not require any modifications to
the engine [2]. Study on alcohol fuels blended with standard diesel fuels has been studied extensively
on CI engines to observe the engine performance and emissions. However the use of n-butanol fuel is
still not widely explored by the researchers.

Butanol is produce by fermentation of biomass; algae, corn and plant materials that contain
cellulose. There are four of butanol isomers namely normal butanol, CH3CH2CH2CH2OH (n-butanol),
secondary butanol CH3CH2CHOHCH3 (2-butanol), isobutanol (CH3)2CH2CHOH (i-butanol), and ter-
butanol (CH3)3COH (t-butanol). Each structure of butanol has the same formula and amount of heat of
energy. Despite their similarity, they have different solubility properties [3].

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution

of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Published under licence by IOP Publishing Ltd 1

3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

Using butanol diesel fuel blends in diesel engines and its effects on engine performance and
exhaust emissions have been investigated in several literatures. Yao et al. [4] investigated the effects
of butanol ratios (5%, 10% and 15%) by volume in diesel blends on six cylinders diesel engine
equipped with common rail injection system. Throughout the results increasing butanol blends
reflected to reduction of CO and soot emissions while little increased in BSFC. Rakopoulos et al. [5-7]
performend the experimental tests on single-cylinder, compression–ignition, direct injection, naturally
aspirated diesel engine. Based on the data, with addition of n-butanol (8, 16 and 24%, by vol.) to
diesel fuel increased the BSFC, BTE and HC emissions while significantly decreased CO, NOx and
soot.

Presently there are limited numbers of study on combustion and emission characteristics using n-
butanol as an alternative fuel. Thus an effort has been done to investigate the use of n-butanol blends
on the water-cooled engine fitted with a high pressure direct fuel injection system from common rail
equipped with turbochargers and exhaust gas recirculation (EGR). The engine was tested at engine
speed 1000rpm and 2500rpm with single brake mean effective pressure (BMEP) level 3.5Bar.

2. Experimental set up

2.1. Fuel Properties
Compared to the other alcohol kinds, n-butanol has more advantages than methanol and ethanol as fuel
substitutions for CI engine. Butanol has a lesser auto-ignition temperature than methanol and ethanol.
Thus, butanol can be ignited easier when combusted in the combustion chamber. Moreover Butanol
has also a higher cetane number, therefore more suitable fuel blends than ethanol and methanol for
diesel fuel. Energy content of the butanol is the highest among the alcohol family thus it released more
energy per unit mass. The physical and chemical properties of butanol indicate that it is capable to
seize the limitations from low carbon alcohols which are methanol and ethanol [8].

Table 1. Physicochemical properties of butanol and diesel fuels.

Property Diesel Fuel Butanol
15-25 96
Research octane number (RON) 40-55 25
Cetane No.
Energy content (Lower heating 42.8 33.1
value) (MJ/Kg)
Heat of vaporization (MJ/Kg) 44.8 36.6
Density at 20 °C (g/ml) 0.829 0.8098
Flash Point (°C) 74 35
Auto ignition temperature (°C) 235 397

2.2. Engine setup
The experimental test setup was conducted on a 4-cylinder, 4-stroke CI engine. The engine was a

water-cooled, fitted with a high pressure direct fuel injection system from common rail and equipped
with turbochargers and EGR. Commercial Diesel fuel produced by Petronas was used as the based fuel
and will be referred to as “Diesel”. Apart of the base fuel, 10% of n-butanol blended with diesel fuel
were tested and referred to as “Bu10”. The engine was operated at engine speeds (1000rpm and
2500rpm) and constant BMEP level 3.5Bar. One of the four engine cylinders was attached with a

Kistler water cooled piezoelectric transducer (Type 6041A) to measure the in-cylinder pressure of the
engine. The pressure transducers were synchronized with kistler cam crank angle encoder type
2713B1 attached to the end crank shaft and the reading is measured by Dewe-5000. The brake torque

of the engine was measured with an eddy-current dynamometer model ECB-200F SR No.617 from
Dynalec Controls. The emissions of the engine are measured by KANE gas analyzer. Figure 1 shows

2

3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

the schematic diagram of the experimental setup. The specifications of the engine are based on Table
2.

B10 Diesel
fuel

In – cylinder Crank angle
pressure sensor Encoder

Eddy current
Dynometer

Exhaust gas
analyzer

Dynamometer Dewetron
controller

Figure 1: Experimental diagram.

Table 2: Engine specifications.

Engine model Isuzu 4JJ1
Type Inline 4 – cylinder
Injection system Common rail direct injection
Bore x stroke 95.4mm x 104.9mm
Displacement 3.0L
Compression ratio 17.5 to 1
Max power at 2500 rpm 61kW
Max torque at 1800 rpm 280Nm

3. Results and discussion

3.1. Combustion characteristics
The in-cylinder pressure profile of a 4-cylinder, 4-stroke common rail direct injection CI engine are
presented. Figure 2 depicts the combustion profile at engine speed 1000rpm with constant
BMEP=3.5Bar. The graph denoted as the scale graph of in-cylinder pressure in the range -60° to 60°
CA. The circle indicates the specified area of the analysis at peak combustion.

3

3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

Pressure (Bar) Diesel
60 Bu10

Specified 50
area 40

30

20

10

-70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70
Crank angle (CA)

Figure 2. In-cylinder pressure at engine speed 1000rpm.

Figure 3 shows the specified graph with smaller scale in the range of -20° to 20°CA. Based on the
graph two stage of in-cylinder peak pressure can be observed under 1000rpm engine speed at constant
BMEP=3.5Bar. The resulted peak is reflected by the pilot and main injection strategy of the engine
behavior. During first stage, the peak in-cylinder pressure decreased as the torque increased to a high
load conditions. Bu10 indicates lower first and second peak in-cylinder pressure by 5.4% and 2.4%
respectively compared to diesel fuel. This phenomenon is due to the lower auto ignition of the fuel
properties [9]. The cetane number of the blended fuel decreases as 10% of n-butanol was mixed with
diesel fuel. Thus, less fuel combusted at the first and second stage of combustion when more n-butanol
is blended hence reflected to lower heat release for both stages.

Pressure (Bar) Diesel
Second 60 Bu10
peak
First
peak 50

40

30

20

10

-20 -10 0 10 20
Crank angle (CA)

Figure 3. Focus area of peak pressure at engine speed 1000rpm.

Figure 4 shows the in-cylinder pressure at engine speed 2500 with constant BMEP=3.5Bar. The
graph indicates scale of combustion profile in the range of -60° to 60° CA. The circle indicates the

4

3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

specified area of the analysis at peak combustion. The in-cylinder pressure is directly proportionally to
the engine speed, thus increase of in-cylinder peak pressure can be observed.

Pressure (Bar) Diesel
80 Bu10

Specified 70
area 60

50

40

30

20

10

0

-70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70
Crank angle (CA)

Figure 4: In-cylinder pressure at engine speed 2500rpm.

Figure 5 denoted as the smaller scale of peak combustion in the range of -20 to 20° CA. The
combustion profile shows similar trend of injection strategy. Bu10 indicates 4.4% and 2.1% of
reduction for both first and second peak in-cylinder pressure respectively.

Second Pressure (Bar) Diesel
peak 80 Bu10
70
First 60
peak 50
40
30
20
10

-20 -10 0 10 20
Crank angle (CA)

Figure 5: Focus area of peak pressure at engine speed 2500rpm.

3.2. Emissions characteristics
Figure 6 shows the effect of n-butanol/diesel fuel blends on exhaust temperature at engine speeds
1000rpm and 2500rpm with constant BMEP=3.5Bar. It was observed that n-butanol/diesel fuel blends
resulted to lower exhaust temperature than diesel fuel by 7.5% and 5.2% at engine speeds 1000rpm

5

240 Diesel
220
200 Bu10
NO (PPM) 180
x 160
140
IOP Publishing
3rd International Conferen1c2e0 of Mechanical Engineering Research (ICMER 2015)
IOP Conf. Series: Materia1l80s00Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048
60
40
20
and 2500rpm respectivel0y. This is due to the lower energy content and the cetane number of n-
1000 Engine speed (RPM) 2500
butanol/diesel fuel blends [9, 10].

300 (a)

Exhaust temperature (°C) 280 Diesel
260
240 Bu10

220
200
180
160
140
120
100
80
60
40
20
0
1000 2500

Engine speed (RPM)

(b)

Figure 6: Exhaust temperature at engine speed 1000 and 2500rpm.

Figure 7 shows NOx emissions at engine speeds 1000rpm and 2500rpm with constant
BMEP=3.5Bar. It was observed that NOx emissions decreased at engine speeds 1000rpm and 2500rpm
by 73.4% and 11.3% than diesel fuel respectively. The emissions of NOx strongly related to in-
cylinder temperature during combustion. The mixture of n-butanol/diesel fuel blends lead to lower
combustion temperature due to lower heating value and oxygen content of n-butanol fuel properties
[11, 12].

240 Diesel
220
200 Bu10
NO (PPM) 180
x 160
140
120
100
80
60
40
20
0

1000 Engine speed (RPM) 2500

300 (a)

Exhaust temperature (°C)Fig2u80re 7: NODx ieemseilssions at engine speed 1000 and 2500rpm.

260 Bu10
240
4. Conclusion 220
As for the conclusion,1280th00e influences of 10% n-butanol blend with diesel fuel on combustion and
emissions characteristic1s60were investigated under two different engine speeds (1000rpm and 2500rpm)
with constant BMEP=311.524B00 ar. The main results can be summarized as follows.
(i) Combustion ch1a80r00acteristics of n-butanol/diesel fuel blends indicates lower first and second
peak pressure by605.4% and 2.4% for engine speed 1000rpm and 4.4% and 2.1% for engine
speed 2500rpm c24o00mpared to diesel fuel respectively.
0
(ii) Exhaust temperature of n-buta1n0o0l0/diesel fuel blends are2r5e0d0uced significantly by 7.5% and
11.3% for both engine speeds 1000rpmEnagninde2s5p0ee0drp(RmPcMo)mpared to diesel fuel respectively.
(b)

6

3rd International Conference of Mechanical Engineering Research (ICMER 2015) IOP Publishing

IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

(iii) Reduction of NOx emissions using n-butanol/diesel fuel blends by 73.4% and 11.3% for both
engine speeds 1000rpm and 2500rpm compared to diesel fuel respectively.

Acknowledgements
Appreciation and acknowledgement to the Ministry of Higher Education (KPT) for providing author
the scholarship under My Brain 15 scheme and financial support from Universiti Malaysia Pahang
grant.

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performance and emissions 2011 Fuel 90 2467-2472
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jection on HD diesel engine performance and emissions 2010 Fuel 89 2191-2201,.
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[10] Valentino G, Iannuzzi S, and Corcione FE Experimental Investigation on the Combustion and
Emissions of a Light Duty Diesel Engine Fuelled with Butanol-Diesel Blend 2013 SAE
International
[11] Siwale L, Kristóf L, Adam T, Bereczky A, Mbarawa M, Penninger A, et al., "Combustion and
emission characteristics of n-butanol / diesel fuel blend in a turbo-charged compression ignition
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[12] Siwale L, Kristóf L, Bereczky A, Mbarawa M, and Kolesnikov A Performance, combustion and
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[14] Chen G, Shen Y, Zhang Q, Yao M, Zheng Z, and Liu H Experimental study on combustion and
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[15] Chen Z, Wu Z, Liu J, and Lee C Combustion and emissions characteristics of high n-butanol /
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IOP Conf. Series: Materials Science and Engineering 100 (2015) 012048 doi:10.1088/1757-899X/100/1/012048

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8

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Investigation of emissions characteristics of secondary butyl alcohol-gasoline
blends in a port fuel injection spark ignition engine

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MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

Investigation of emissions characteristics of
secondary butyl alcohol-gasoline blends in a
port fuel injection spark ignition engine

I.M. Yusri1,*, Rizalman Mamat1,2, A. Aziz1,2, A.F. Yusop1,2, Omar I. Awad1 and S.M. Rosdi1
1 Faculty of Mechanical Engineering, Universiti Malaysia Pahang (UMP), 26600 Pekan, Pahang,
Malaysia
2Automotive Engineering Centre, Universiti Malaysia Pahang (UMP), 26600 Pekan, Pahang,
Malaysia

Abstract. Exhaust emissions especially from light duty gasoline engine
are a major contributor to air pollution due to the large number of vehicles
on the road. The purpose of this study is to experimentally analyse the
exhaust pollutant emissions of a four-stroke port fuel spark ignition
engines operating using secondary butyl alcohol–gasoline blends by
percentage volume of 5% (GBu5), 10% (GBu10) and 15% (GBu15) of
secondary butyl- alcohol (2-butanol) additives in gasoline fuels at 50% of
wide throttle open. The exhaust emissions characteristics of the engine
using blended fuels was compared to the exhaust emissions of the engine
with gasoline fuels (G100) as a reference fuels. Exhaust emissions analysis
results show that all of the blended fuels produced lower CO by 8.6%,
11.6% and 24.8% for GBu5, GBu10 and GBu15 respectively from 2500 to
4000 RPM, while for HC, both GBu10 and GBu15 were lower than that
G100 fuels at all engine speeds. In general, when the engine was operated
using blended fuels, the engine produced lower CO and HC, but higher
CO2.

1 Introduction

Climatic change of the earth have triggered a global warning to each corner of this earth
due to its adverse effects to each living creatures. Based on the estimation done by
International Energy Agency (IEA), a rose by 53% in global energy consumption is
foreseen by the year of 2030 [1]. Malaysia alone estimated to have an increment of gross
domestic product (GDP) by 4.6% in between 2004 to 2030, which indicate that increased of
GDP by 1% approximately resulted to growth of energy demand by 1% [2]. Transportation
sector are one of the major contributor in rise of energy demand mainly from gasoline and
diesel engine vehicles which consumed depleted fossilized fuels [3-5]. Perhaps one of the
potential solution that could possibly bring back the balanced in energy consumption and
the climatic change in this world is by introducing the biofuel in the transportation areas[6-
7].

* Corresponding author: [email protected]

© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative
Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).

MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

The use of alternative clean biofuels such as methanol, ethanol and butanol is one of the
method to reduce the dependency on the energy demand for fossilized fuels in spark
ignition engine [8-10]. However for the past few years the investigation of methanol and
ethanol have received considerable critical attention with less attention paid to the butanol
as a sustainable fuel substitutions alternative. Basically butanol is a four carbon chain of
alcohol types. It exist in four types of isomers; 1-butanol, 2-butanol, tert-butanol and iso-
butanol. Each types of isomer have different physicochemical properties. Butanol are
considered as an advanced biofuel due to its superior characteristics compared to other
alcohol family members [11-13]. Compared to methanol and ethanol butanol have the
nearest fuel properties similarity to the gasoline fuel such as stoichiometric air fuel ratio,
latent heating value, energy content, octane number and auto ignition temperature thus make
it more suitable to be blended with gasoline fuel [14-16]. Furthermore butanol can be
transported through the existing fuel pipeline as it is less corrosion. With all of the
advantages offered by butanol without doubt it has been proposed as a next generation
biofuel as an alternative to the conventional fuels [17-18].

Taking this into account, n-butanol undoubtedly to have a very remarkable prospective
because its properties are almost similar to gasoline fuels. This can reduce the efforts that to
be done to adapt their current range of vehicles to be able to run on butanol-gasoline
blends. Various precious study has been done to investigate the butanol additive in a
gasoline fuels. Among the recent study are from Feng et al. [19]. They used to investigate
the effects of adding butanol additives by 30% and 35% of percentage volume in a gasoline
fuels using single cylinder spark ignition (SI) engine. Based on his heat release analysis,
butanol addition indicates higher knocking resistance. Szwaja and Naber [20] reported that
the early combustion duration and length of combustion duration in a SI engine were
shortened with increased of n-butanol volumes. In another study shorter early combustion
duration stage, better combustion stability and faster combustion was stated by other
researchers [21-22].

Galloni et al. [23] studied the effect of butanol and its blends by (20% and 40% of
butanol volume) on engine performance and emissions by using port fuel injected
turbocharged SI engine. The author found that the engine torque and thermal efficiency
drop by approximately 4% for butanol-gasoline blends compared to the gasoline fuels.
Singh et al. [24] conducted an experimental study on 5%, 10%, 20%, 50% and 75% of
butanol volume percentage in a gasoline fuels with medium duty transportation SI engine.
They found that reduction of brake thermal efficiency (BTE) and exhaust gas temperature,
brake specific nitrogen oxides (BSNO), brake specific carbon monoxides (BSCO) and
smoke emissions for butanol-gasoline blends compared to the pure gasoline fuels.
Elfasakhany [25] analyzed the effects of performance and emissions of an engine fueled
with low proportion of n-butanol by 0, 3, 7 and 10% volume n-butanol-gasoline blends.
Experimental investigation have been done without any modifications on the SI engine
systems. Based on the results show that engine in-cylinder pressure, torque, and exhaust
gas temperature of the engine slightly decrease when n-butanol-gasoline blended fuels are
used. Moreover blended fuel also produced lower CO, CO2 and HC concentrations
compared to those of neat gasoline. Yacoub et al. [26] examined butanol-gasoline blends
with carbon numbers C1 to C5. The results showed that all n-butanol blends had lower CO
and UHC emissions. Alasfour [27-28] evaluated the effect of using 30% n-butanol by
volume blended with gasoline in a single-cylinder SI engine. He found that the lower
engine efficiency by 7% compared to pure gasoline fuel.

This study aim to integrate the existing experimental investigation on combustion
performance and emissions characteristics of a SI engine fueled with butanol-gasoline
blends in a low proportion of butanol mixture by 5%, 10% and 15% at 50% of wide throttle
open (WTO) varied from 1000 to 4000 RPM with interval of 500 RPM. Butanol used in

2

MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

this study are from the second butanol family namely secondary butyl alcohol (sec-
butanol). This research can contribute to further the knowledge on the effects of butanol
mixture in a four cylinder four strokes port fuel injection SI engines. In addition, as far as
the author concern there are little attention has been paid to butanol-gasoline blends
mixture from the secondary butyl alcohol family. The investigation of emissions
characteristics analyses were performed; in particular CO, CO2, and HC.

2 Experimental setup

2.1 Materials

In this research investigation, engine testing was done with gasoline fuels as a reference
fuels (G100) and blends of 5%, 10% and 15% by volume of sec-butanol in a gasoline fuels
indicated as GBu5, GBu10 and GBu15 respectively. Briefly, 2-butanol was added into
gasoline fuels and mixed at low stirring rate using an electric magnetic. The mixture was
stirred continuously for 15 minutes at room temperature to prepare the blended fuels.
Gasoline fuels was bought from local petrol station and stored in the lab inside the proper
container. The 2-butanol with percentage of purity of 99.5% were bought from Merck
distributor in Malaysia as in Figure 1. The properties of G100 and 2-butanol fuels are
specified in Table 1. The fuel blends were prepared just before the start of experiment to
ensure that the fuel mixture was homogenous.

Fig 1. 2-butanol purchased through Merck distributor in Malaysia

2.2 Experimental procedure

In this experimental study, the experiments were performed on a Mitsubishi 1.8 single
overhead camshaft (SOHC) engines with four cylinders, four stroke and spark ignition
engines. The engine specifications are specified in Table 2. Figure. 2a and b present the
actual engine and schematic diagram of the engine experimental test setup. A 100 kW of
Dynalec Controls eddy current dynamometer was fixed to the engine in order to apply a
consistent 50% of WTO conditions. The load exerted on the engine is measured by the load
cell connected to the eddy current dynamometer. All the experiments are conducted and the
results are recorded under steady state conditions. Fuel consumption was occupied using
AIC fuel flow rate meter with an accuracy of 1% reading. Air consumption was recorded
using Benetech GM8903 hot wire type anemometer with the air speeds resolution by 0.001
m/s. The relative air fuel ratio was measured using an accurate calibrated KANE gas

3

MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

analyzer version autoplus 5-2. Sensitivity and measurements accuracy of the exhaust gas
concentration have been described in Table 3.

Table 1. Properties of gasoline and 2-butanol [11,21,29-30].

Property Gasoline 2-butanol
0.44 – 0.50 -
Molar C/H ratio 736 806.3
44, 300 33, 000
Density (kg/m3)
14.6 11.1
Latent heating value 95/85 101/92~97
(kJ/kg) 228 – 470 406.1
Stoichiometric air/fuel 27 – 225 99.5
ratio 349 551

RON/MON 1.4 – 7.6 1.7 – 9.8
~33 ~48
Auto – ignition
temperature (°C)

Boiling point (°C)

Heat of vaporization
(kJ/kg)
Flammable limits
(%volume)

Laminar flame speeds [31]

Table 2. Engine specifications.

Engine descriptions 81.0mm x 89.0mm
Bore x Stroke
Piston displacement 1834cc
Compression ratio
Fuel injection type 9.5:1

Max power ECI-Multi (Electronically Controlled
Max torque Multi-point Fuel Injection
86kW @ 5500rpm

161Nm @ 4500rpm

Table 3. Sensitivity and measurements accuracy of instruments used for measuring the exhaust gas
concentration.

Exhaust gas Measurements domain Measurement accuracy
CO 0 – 21% +/- 5% or 0.06% volume-1
CO2 0 – 16% +/- 5% or 0.5% volume-1
HC 0 – 5000ppm
+/- 5% or 12ppm volume-1

4

MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

Dyno external water
tank

Engine dynamometer

Engine

(a)

Exhaust gas
7

T2 T4 11
9 18 2 10

T3 T5

T1 5
6
Fuel drain
Air intake valve

Fuel return valve

14
4

12 13

3

(b)

Fig 2. Engine test bed and test instruments (a) actual and (b) schematic

1. Engine test setup 8. In-cylinder pressure sensor
2. Eddy current dynamometer 9. Kistler crank encoder
3. Dyno controller 10. Dyno external water tank
4. Fuel tank 11. Engine external water tank
5. Fuel pump 12. Dewe-5000 combustion analyzer
6. Air flow rate 13. Computer
7. Exhaust gas analyzer 14. Data logger

5

MATEC Web of Conferences 90 , 01036 (2017) DOI: 10.1051/matecconf/20179001036
AiGEV 2016

2.3 Emissions index

The emissions data were reported using emission index basis to allow comparisons to be
made between the different sizes of engines and fuel chemical compositions.
According to Saxena and Jotshi [32], the emissions index (EI) can be calculated using the
following equations:

EIi § Xi X HC ·§ F MVi · (1)
¨©¨ X CO X CO2 ¸¸¹ ¨¨© MW f ¸¹¸

Where it can be simplified as:

EICO § CO · u100% (2)
EICO2 ¨ ¸ (3)
EI HC © CO CO2 HC ¹ (4)

§ CO2 · u100%
¨ CO2 ¸
© CO HC ¹

§ HC · u100%
¨ ¸
© CO CO2 HC ¹

Where CO, CO2 and HC are in parts per million (PPM).

3 Results and discussions

In this study, the sec-butanol-gasoline blended fuels are examined in three different
proportions (5%, 10% and 15%) and are compared to the reference fuels neat gasoline fuels
in terms of emissions characteristics. The quantity of GBuX represents a blend consisting
of X% of sec-butanol by percentage of volume, e.g., GBu5 indicates a blend consisting of
5% of 2-butanol in 95% of gasoline. Four test fuels were used in this study: gasoline
(G100); 5% of 2-butanol (GBu5); 10% of butanol (GBu10); and 15% of (GBu15).
Incomplete combustion and poor mixing of air and fuel are the major causes of CO
productions [33].In Figure 3 presents effects of sec-butanol additions in gasoline fuels to
the carbon monoxides (CO) emissions index (EI). From Figure 3, a slight increase was
observed for blended fuels from engine speeds 1000 to 2500 RPM. However, as the engine
speeds achieved engine speeds of 2500 to 4000 RPM, G100 fuels produced higher CO
emissions as compared to blended fuels. The average reduction of CO emissions was
calculated for blended fuels compared to G100 fuels in order to distinguish the effects of
sec-butanol addition in G100 fuels. A significant of reduction by average of 8.6%, 11.6%
and 24.8% for GBu5, GBu10 and GBu15 respectively throughout the speed range of 2500
to 4000 RPM. Hence, the blended fuels is more combustible than the G100 fuels. It appears
that this result is in accordance with the studies which have already been reported such as
in Ref. [21,34].

6

















S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

RESULTS

Combustion Analysis Method

For tracking the combustion process with the crank angle, a fiber-optic based direct in-cylindrical pressure sensor and
magnetic encoder were used. The TFX combustion analyzer software captured the pressure variations. It has a size range
of 0–200 bar and a sensitivity of 1.12 mV-psi. At 200 successive cycles, the average data was acquired. ROHR was
calculated using the first rule of thermodynamics. The heat released was calculated by calculating the heat transfer from
the cylinder to the wall. Eq. (1) was used to compute the rate of heat loss based on the crank angle degree.

1 + 1 1 + ℎ (1)
= − −

Where, Q is heat release during combustion, is crank angle degree, is specific heat ratio and is instantaneous
volume during combustion. ROHR defined as the rate of chemical energy released by the combustion process. The ROPR
was calculated by using Eq (2).

+1 − −1 (2)
= +1 − −1

Where, is crank angle and is cylinder pressure. MFB defined as a function of cumulative of percentage energy
released by the heat of fuel. It also can be defined as progress of the combustion. The MFB was estimated by using Eq.(3).

= 1 − [− ∆− 0)] +1 (3)
(

Where is crank angle, 0 is combustion starting angle, ∆ is the total combustion duration (MFB=0 to MFB=1),
and m are adjustable weibe parameter.

Fuel Preparation

Before data collection, the fusel oil and gasoline were blended with an electrical stirrer for 5 minutes. The parameters
of the gasoline and fusel oil that were used in the experiment are listed in Table 3. The parameters of gasoline-fusel oil
mixtures are shown in Table 4 below. The density of the mixture was measured using an ASTM D4052 technique and a
portable specific gravity metre. The octane number, on the other hand, was computed using the weight of a mole of
molecule. The research octane number (RON) was determined by using an ASTM D2699-compliant portable octane
number device. The heating value of the fuel was tested with an ASTM D240 calorimeter bomb.

Table 3. Properties of gasoline and fusel oil

Gasoline Fusel Oil
122-138 [26]
Boiling Temperature, °C 27-225 501-874 [26]

Latent Heat of Vaporization, kJ/kg 349 29 [27]
41[21]
Lower Heating Value, MJ/Kg 44 41.6
12.5
Flash Point, °C -45
847
Auto Ignition Temperature, °C 257 0.61
106.8[6]
Stoichiometry 14.7
Density, kg/m3 737
Viscosity, mm2/s 0.5-0.6

Research Octane Number 95

Table 4. The properties of fusel oil blends

Properties Test Standard Fusel 10% Fusel 20% Fusel 30%
Blend (F10) Blend (F20) Blend (F30)
Density (kg/m3)
Stoichiometry (weight) ASTM D4052 776 783 794
13.8
Octane Number Mole Calculation 12.8 13.2 98.6
Heating value (MJ/kg) 39.4
ASTM D2699 96.1 97.2

ASTM D240 42.6 41.6

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

The fuel usage was measured using an AIC-1204 HR 2000 model fuel flow metre with 0.01s sensitivity. To deliver
gasoline and keep the pressure at 35 psi, a 12V inline fuel pump is used. Eq. (4) was used to calculate the BSFC.

= ṁ (4)


Where ṁ is fuel flow and is engine power.

Instrument Preparation

A Kane Auto-plus 5-2 gas analyzer was used to record the exhaust emission components and relative air-fuel ratio.
The air-fuel ratio, as well as exhaust gas emissions such as NOx, CO, and HC, are measured. A Benetech GM8903 hot-
wire anemometer with an air speed resolution of 0.001m/s was used to monitor the intake air flow rate. Air intake flow
can be used to determine the fuel ratio in stoichiometry, or vice versa. The temperatures of the engine oil, suction air, and
exhaust gas were then measured with K-type thermocouples and data recorders (Picolog TC-08). To keep the temperature
between 85 and 90 degrees Celsius, the engine was cooled by flowing water from an external water tank.

DISCUSSION

Combustion - In-Cylinder Pressure

For engine speeds of 2000 rpm, Figure 2 shows comparisons of in-cylinder pressure versus crank angle degree (CAD).
In-cylinder pressure is shown in Figures. 2(a) to 2(d) for a throttle load of 10% to 40%. Before taking the in-cylinder
pressure data, the driving pressure was utilised to calibrate the TFX software and tallied with hand calibration. During
engine running, the maximum in-cylinder pressure rises by 3-5 MPa, and peak pressure gasoline fuel is higher than other
fuel blends. According to studies, as engine load increases, so does in-cylinder pressure. In comparison to fusel oil, the
higher in-cylinder pressure caused by gasoline fuel has a larger heating value [7]. The increase in cylinder pressure comes
as a result of the charge flow volumetric efficiency into the engine cylinder. Fusel oil mixtures, on the other hand, burned
at a faster pace than gasoline. When compared to gasoline, the fusel oil blends produced peak pressure 2-3 CAD earlier.
Not only did the peak pressure drop, but so did the rate of pressure rise. When compared to gasoline, it has a higher
vaporisation rate and a faster laminar flame velocity, which helps to shorten the time it takes for flame kernels to form
and develop [26]. Fusel oil blends in gasoline were increased, which improved cylinder charge cooling, resulting in lower
combustion and temperature [28].

In-cylinder pressure (MPa) 7 G In-cylinder pressure (MPa) 7 (b) Engine load 20% G
(a) Engine load 10% F10 6 F10
F20 5 F20
6 F30 4 F30
5 Motoring 3 Motoring
4
3

2 2

1 1

0 0
-40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100

Crank angle (Degree) Crank angle (Degree)

In-cylinder pressure (MPa) 7 G In-cylinder pressure (MPa) 7 (d) Engine load 40% G
6 (c) Engine load 30% F10 6 F10
F20 5 F20
5 F30 4 F30
Motoring 3 Motoring
4

3

22

11

0 0
-40 -20 0 20 40 60 80 100 -40 -20 0 20 40 60 80 100

Crank angle (Degree) Crank angle (Degree)

Figure 2. In-cylinder pressure for gasoline and fusel oil blends

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

Rate of Pressure Rise

The Rate of Pressure Rise (ROPR) was observed at 2000 rpm and 10-40% engine load in Figure 3. Its values were
calculated using the first derivative of in-cylinder pressure. It also reflects the heat release rate [29]. As can be seen in the
graph, ROPR increases as engine load increases. It has increased as charge density and volumetric efficiency in engine
cylinders have increased. For 10-40% engine load, the maximum ROPR is 3.5-6.5 Bar/CA. When fusel oil mixtures are
increased, however, ROPR decreases. Combustion pressure was reduced compared to gasoline by a lower premixed
burning rate due to higher water content and a shorter ignition delay of fuel blends. The burning velocity of increased
combustion has a significant impact on ROPR [30]. When comparing fusel oil blends to gasoline, it can be seen that peak
ROPR occurs slightly earlier and has a shorter duration. At high engine loads, this tendency became more noticeable. The
molecular structure and reaction kinetic characteristics of alcohol fuel were characterised by Chen et al. [31]. The
hydroxyl moiety in fusel oil is linked to the hydrocarbon chain. At low temperatures, the presence of the hydroxyl moiety
weakens the C-H bond, allowing hydrogen abstraction processes to dominate [32].

8 G (a) Engine speed 2000 rpm 8 G (b) Engine speed 2000 rpm

7 F10 Engine load 10% 7 F10 Engine load 20%

ROPR (Bar/CA) 6 F20 ROPR (Bar/CA) 6 F20

5 F30 5 F30

44

33

22

11

0 10 20 30 40 0 10 20 30 40
-40 -30 -20 -10 0 -40 -30 -20 -10 0

ROPR (Bar/CA) 8 CAD ROPR (Bar/CA) 8 CAD
7 G (c) Engine speed 2000 rpm 7 G (d) Engine speed 2000 rpm

F10 Engine load 30% F10 Engine load 40%
6 F20 6 F20

5 F30 5 F30

4 4

3 3

2 2

1 1

0 0
-40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40

CAD CAD

Figure 3. ROPR for gasoline and fusel oil blends

Rate of Heat Release

Figure 4 displays the Rate of Heat Release (ROHR) with an engine load of 10-40% and a speed of 2000 rpm. The
ROHR values were derived from the in-cylinder pressure. The rate at which chemical energy from a fuel is released by
the combustion process is known as ROHR [33]. It indicates that as engine load increases, so does the peak of ROHR. It
rises as the in-cylinder pressure rises as the throttle is opened to increase the volumetric charge in the engine. Then, when
comparing fusel oil blends to gasoline, the peak of ROHR occurred slightly sooner for fusel oil blends. Godwin et al. [34]
stated that earlier of ROHR was due to increased flame propagation and combustion flame speeds. They also stated that
the peak of ROHR is dependent on the amount of fuel used by the participant, whether it is a rich or lean mixture. Because
of free radical propagation and the faster laminar flame speed associated with the location of the OH group, oxygenate
fuel blends ignited earlier than gasoline. However, when compared to gasoline, the peak of ROHR for fusel oil blends is
modest. The reduced heating value and water content of fusel oil blends, which worsen combustion when compared to
gasoline, result in a lower peak ROHR [35]. As a result, it contributes to a lower combustion cylinder temperature and
reduced NOx emissions.

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

ROHR (J/CA) 60 G (a) Engine load 10% ROHR (J/CA) 60 G (b) Engine load 20%
50 F10 50 F10

F20 F20
40 F30 40 F30

30 30

20 20

10 10

0 0
-40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40

CAD CAD

60 (c) Engine load 30% 60 (d) Engine load 40%
G G

50 F10 50 F10
F20
ROHR (J/CA) ROHR (J/CA) 40 F20
40 F30 F30
30
30

20 20

10 10

0 0
-40 -30 -20 -10 0 10 20 30 40 -40 -30 -20 -10 0 10 20 30 40

CAD CAD

Figure 4. ROHR for gasoline and fusel oil blends

Mass Fraction Burn

The Mass Fraction Burn (MFB) curve may be used to illustrate flame structure very well. Figure 5 depicts the progress
of MFB combustion with a 10-40% engine load at 2000 rpm. It demonstrates that the progress of fusel oil mixes has
switched in the direction of gasoline. MFB for blended fuels shifts due to greater flame speed during combustion flame
propagation. Due to the higher oxygen content in fusel oil, the flame speed of combustion is faster. It happens 1-2 degrees
earlier than the other fuels. Furthermore, due to the higher oxygen concentration, the start of combustion (SOC) of fusel
oil blends (0-10%) occurs slightly earlier. Then, due to faster combustion, the duration of combustion (DOC) is reduced
at 10-90 percent MFB [36]. During 40 percent engine load, it was shown to be shorter at 30 CAD for fusel oil mixes
compared to 38 CAD for gasoline. When comparing fusel oil blends to gasoline, the end of combustion (EOC) at 90-100
percent MFB is 2 degrees earlier for fusel oil blends. Elfasakhany [37] found a similar finding, stating that complete
combustion occurs when the reactivity of the fuel is high, as a result of a shorter ignition delay and greater flame speed
combustion.

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

Mass Fraction Burned G (a) Engine load 10% Mass Fraction Burned 1.0 (b) Engine load 20%
1.0 F10 EOC 90% MFB 0.8 EOC 90% MFB
0.6
F20 0.4 50% MFB

0.8 F30

0.6 50% MFB

0.4

0.2 SOC 10% MFB DOC 0.2 SOC 10% MFB DOC
0.0 0.0

-40 -30 -20 -10 0 10 20 30 -40 -30 -20 -10 0 10 20 30
CAD CAD 30

(c) Engine load 30% (d) Engine load 40%

Mass Fraction Burned 1.0 EOC 90% MFB 1.0 EOC 90% MFB

0.8 0.8 Mass Fraction Burned

0.6 50% MFB 0.6 50% MFB
0.4 0.4

0.2 SOC 10% MFB DOC 0.2 SOC 10% MFB DOC
0.0 0.0

-40 -30 -20 -10 0 10 20 30 -40 -30 -20 -10 0 10 20

CAD CAD

Figure 5. MFB for gasoline and fusel oil blends

Brake Specific Fuel Consumption

The effect of employing gasoline and fusel oil mixes on the Brake Specific Fuel Consumption (BSFC) for an engine
speed of 2000 rpm with a 10-40% throttle position is shown in Figure. 6. When fusel oil mixes were increased in the same
engine load, BSFC rose 5-22 percent on average compared to gasoline. Increased BSFC occurs in fusel oil blends
compared to gasoline due to the high density of fusel oil. Calam et al. [18] found that because fusel oil has a higher density
than gasoline, the amount of mass fuel taken into the engine cylinder increases. Then, Thangavelu et al. [38] said that the
BSFC increased due to the alternative fuel's reduced heating value of over 30% when compared to gasoline. Fusel oil's
poor heating value makes it difficult to improve engine performance [27]. Furthermore, the increase in BSFC is dependent
on the proportion of blended fuel. For all test fuels, however, the BSFC increased as engine load rose. Due to higher
engine brake heat, greater engine load causes an increase in BSFC [39].

Figure 6. BSFC for gasoline and fusel oil blends

Brake Thermal Efficiency
Brake Thermal Efficiency (BTE) is shown in Figure 7 with an engine speed of 2000 rpm and a load of 10-40%. It is

the quantity of fuel used for each unit of power or work performed per hour. When the engine load is raised, BTE
increases. It rises as the density of the air/fuel charge in the engine cylinder rises as the throttle is opened. According to

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

Bendu et al. [40], BTE rises as the maximum gas temperature rises with increased engine load. Furthermore, the earlier
onset of combustion results in a greater gas temperature and, most likely, a higher combustion efficiency. When fusel oil
mixtures are increased, BTE decreases. When compared to gasoline, BTE decreases by 13-16% for all engine loads. Fusel
oil has a reduced heating value, which helps to reduce BTE. Deng et al. [41] obtained a similar finding, stating that the
BTE is lower due to heat loss passed to the cylinder wall. BTE was reduced due to alcohol-gasoline blends contributing
to an increase in effort lost in the compression process, according to Li et al. [36].

BTE (%) 40 G Engine speed 2000 RPM
F10

35 F20
F30

30

25

20

15

10

5

0
10 20 30 40

Engine Load (%)

Figure 7. BTE for fusel oil-gasoline blends

Emission Analysis - Oxides of Nitrogen

Figure 8 depicts NOx emissions at 10-40 percent load and 2000 rpm. NOx generation is influenced by in-cylinder
temperature, ignition time, and oxygen content in the fuel, according to Wan et al. [42]. The rise in NOx caused by
increased in-cylinder pressure and temperature [43]. Shameer & Ramesh [44] discovered that increased NOx emissions
are caused by a greater combustion temperature, which leads to an intensified nitrogen-oxygen interaction.

1100 G Engine speed 2000 rpm
1000 F10
NOx (ppm) F20
900 F30
800
700
600
500
400
300
200

10 20 30 40
Engine load (%)

Figure 8. NOx for fusel oil-gasoline blends

By opening the throttle position, the in-cylinder pressure is increased due to the increased density of the air/fuel
combination. When fusel oil mixes were increased, however, NOx decreased by 18% to 36%. Every engine test load
showed the same pattern. When compared to gasoline, NOx levels are lower due to lower in-cylinder pressure. When
alcohol fuel was used, NOx emissions were reduced due to lower in-cylinder temperatures [44]. Because alternative fuel
has a lower heating value and a larger latent heat of vaporisation, the maximum in-cylinder temperature was reduced
when it was mixed with gasoline, according to Turner et al. [45].

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Hydrocarbon

The element hydrocarbon (HC) is made up primarily of carbon and hydrogen. It is a result of incomplete combustion
caused by a lack of oxygen, a high temperature, and a long combustion period [8]. Figure 9 shows the HC emission trend
at a 2000 rpm engine speed and a 10-40% throttle setting. When the engine load is increased, the HC emissions drop.
During engine cycles, HC levels drop due to complete combustion. Masum et al. [46] came to a similar conclusion.
During complete combustion, they mentioned an increase in NOx and in-cylinder temperature. According to Hossain and
Davies [47], HC emissions from gasoline are higher than those from alternative fuels due to a higher temperature response
in the in-cylinder engine during combustion. The full combustion of alternative fuels, which has a higher oxygen content,
led to the reduction in HC emissions described by [19]. When fusel oil mixes are increased in gasoline, HC levels drop
when compared to gasoline. In comparison to gasoline, HC is reduced by 3-4 percent on average. The use of alternative
fuel in internal combustion engines reduces HC because it mostly contains oxygen, according to Jaliliantabar et al. [48].
Prbakaran & Viswanathan [49] described a decrease in HC emissions due to higher combustion temperature with higher
engine load.

300
Engine speed 2000 rpm
G

280 F10
F20

260 F30

HC (ppm) 240

220

200

180

10 20 30 40
Engine load (%)

Figure 9. HC for gasoline-fusel oil blends

Carbon Monoxide

Figure 10 shows the carbon monoxide (CO) emissions for various fuel blends at a 2000 rpm engine speed. CO
emissions are the result of incomplete combustion caused by a shortage of temperature and oxygen. CO emissions are
slightly higher at low load than at higher load. When fuel blends were increased at the same engine load, CO emissions
decreased by 7.5 percent -24.5 percent. In cylinder combustion, the reduction of CO for fusel oil blends is well
flammability properties occurred [27]. When the engine load is increased, CO emissions drop. According to Iodice et al.
[50], a decrease in CO emissions might be induced by a quicker flame speed of oxygen concentration in alcohol fuel,
which improves combustion efficiency. Calam et al. [23] determined that higher engine cylinder homogeneity contributes
to better combustion and CO reduction. CO emissions for alcohol fuel are lower than for gasoline, according to Ilhak et
al. [51], because to a higher lamina flame speed, which lowers the temperature inside the engine cylinder.

6

Engine speed 2000rpm G
F10

5 F20

F30

4

CO (%) 3

2

1

10 20 30 40
Engine load (%)

Figure 10. CO emission for gasoline-fusel oil blends

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S. M. Rosdi et al. │ Journal of Mechanical Engineering and Sciences │ Vol. 16, Issue 1 (2022)

CONCLUSIONS

At an engine speed of 2000 rpm and varied throttle loads of 10-40 percent, the performance and engine emission
characteristics of the 1.8L Turbocharged engine fuelled with gasoline and fusel oil mixes are tested. The experimental
study yielded the following conclusions:

1) Fusel oil mixes with lower heating values contributed to reduce in-cylinder pressure, ROHR, and ROPR peaks.
Then, in comparison to gasoline, MFB progressed by 2-3 degrees. It was discovered that the oxygen presence in
fusel oil causes a quicker flame speed of fuel mixture oxidation.

2) A loss in engine performance is caused by a decrease in in-cylinder pressure. As previously stated, the presence
of water slowed the rate of combustion. Then, when compared to gasoline, BTE for fusel oil blends was revealed
to be 13-16% lower.

3) Engine performance suffers as a result of the lower energy level of fusel oil. The higher the density and heat of
vaporisation of fusel oil compared to gasoline, the greater the rise in BSFC fusel oil at 5-22%.

4) Increased engine load and fusel oil mixes lowered HC and CO by 3-4 percent and 7.5-24.5 percent, respectively.
They are reduced as a result of complete combustion. Due to the presence of oxygen in fusel oil, combustion is
completed. When fuel mixtures are increased, NOx levels drop by 18-36 percent. In a cylinder engine,
combustion was completed quickly.

ACKNOWLEDGMENTS

The financial support of Universiti Malaysia Pahang – Malaysia through grant RDU172204, RDU1703147, and
RDU1703314 is greatly acknowledged.

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