Contents lists available at ScienceDirect
Fuel
journal homepage: www.elsevier.com/locate/fuel
Full Length Article
Effects of minor addition of aliphatic (1-pentanol) and aromatic (benzyl
alcohol) alcohols in Simarouba Glauca-diesel blend fuelled CI engine
V. Mathan Raj
a
, L.R. Ganapathy Subramanian
b
, S. Thiyagarajan
c,⁎
, V. Edwin Geo
c
a
Department of Mechanical Engineering, SRM University, Kattankulathur 603203, India
b
Department of Aerospace Engineering, SRM University, Kattankulathur 603203, India
c
Department of Automobile Engineering, SRM University, Kattankulathur 603203, India
ARTICLE INFO
Keywords:
Simarouba glauca
1-Pentanol
Benzyl alcohol
Aliphatic
Aromatic
Ternary blends
ABSTRACT
The objective of the present study is to explore the effects of the minor addition of 1-pentanol and benzyl
alcohol, classified respectively as aliphatic and aromatic type alcohols based on the classified hydroxyl group
position in their molecular structure. Simarouba glauca and diesel blends (B20 and B40) were prepared and
tested to study the CI engine performance, emission and combustion characteristics under different load con-
ditions. To each of the four combination fuel samples prepared for B20 and B40, 1-pentanol and benzyl alcohol
additives were added at 5% and 10% concentrations by volume. Experimental tests for all of the different fuels
were performed in a single cylinder, four-stroke and constant speed CI engine and the engine characteristics
were compared with diesel and biofuel blends. The experimental study reveals that the poor performance of B20
and B40 is enhanced with 1-pentanol (P) and benzyl alcohol (Bn) addition. The improvement in performance is
considerable with an increase in the concentrations of alcohol in B20 and B40 blends. Higher HC, CO and smoke
emissions associated with B20 and B40 blend fuels are reduced with alcohol addition. NOx emissions are also
reduced with the addition of alcohol blends and 1-pentanol shows more promising results in terms of low NOx
emissions compared to benzyl alcohol. Alcohol addition with B20 and B40 extended the ignition delay period
due to low cetane number. However, combustion phasing is reduced as a result of improved combustion. The
outcome of this research work is that poor combustion characteristics of the biofuel-diesel blend can be im-
proved with the minor addition of aliphatic and aromatic alcohol. Except for comparatively higher NOx emis-
sions, benzyl alcohol showed promising results in terms of performance parameters like efficiency, emission and
combustion improvement.
1. Introduction
Diesel engine is a popular prime mover in transportation and agri-
cultural sectors due to its high torque capacity, better fuel economy and
low maintenance cost, compared to gasoline engine [1]. The rapid
depletion of petroleum reserves, fluctuating price of crude oil, en-
vironmental concerns and target-based emission reduction to reach
stringent EURO emission norms desired by various countries, all these
factors demand an alternative, affordable and easily available source of
fuel to replace diesel in a CI engine [2]. Among the various alternative
fuels proposed for a diesel engine, biomass derived fuels (straight ve-
getable oil) have gained much attention particularly because they can
be utilized directly without modifying the existing engine structure [3].
These fuels can address the energy crisis and also reduce the harmful
effects to the environment. Additionally, they reduce the dependency
on petroleum-based fuel. However, a single type of fuel cannot fully
match the performance of a diesel engine and hence a number of new
varieties of blended fuels were explored and their feasibility in the
diesel engine was studied in a few review articles [4,5]. Straight ve-
getable oil possesses high viscosity and poor volatility which affect the
fuel atomization process and subsequent fuel-air mixing. Therefore,
direct use of vegetable oil in a CI engine leads to poor combustion along
with long-term problems like piston ring sticking and injector clogging
[6].
This study uses Simarouba glauca (paradise oil) seed oil as the
straight vegetable oil. The plant grows widely across South America,
Central America and India. Its seed contain 55–65% oil content. The oil
has many industrial uses and it can also be turned into fat or margarine
[7]. About 200 trees can be grown in one hectare of land which gives
6000 kg of seeds that provides around a ton of oil. It was introduced to
https://doi.org/10.1016/j.fuel.2018.07.122
Received 2 March 2018; Received in revised form 15 June 2018; Accepted 25 July 2018
⁎
Corresponding author.
E-mail address: [email protected] (S. Thiyagarajan).
Fuel 234 (2018) 934–943
0016-2361/ © 2018 Elsevier Ltd. All rights reserved.
T
India in 1961, from El Salvador. It can adapt to diverse soil and climate
conditions and it is also drought tolerant [8]. Its major fatty acid
composition is 52–54% oleic acid, 27–33% stearic acid and 11–12%
palmitic acid [9]. A few studies exist on the use of transesterified
paradise oil as a fuel for diesel engines. Devan et al. [10] tested the
biodiesel blends with diesel in a single cylinder CI engine. They pointed
out that while the brake thermal efficiency of biodiesel and its blends
with diesel is lower compared to diesel. They also observed that bio-
diesel reduced HC, CO and smoke emissions significantly with a penalty
of higher NOx emission. To improve the performance of paradise oil,
Devan et al. [11] blended eucalyptus oil in various proportions and
tested it in a CI engine. They observed that low viscosity and better
volatility of eucalyptus oil improved the performance of paradise oil
biodiesel in the CI engine. This also reduced HC, CO and smoke emis-
sions further. On the contrary, NOx emissions increased further due to
improved combustion. Bedar et al. [12] tested Simarouba glauca bio-
diesel blends with diesel, with exhaust gas recirculation (EGR) to re-
duce NOx emissions. They observed that EGR did not affect the per-
formance much and this combination aided in reduced particulate and
NOx emissions.
1.1. Research justification
Numerous methods were proposed by Martin et al. [13] to improve
the performance of a diesel engine using straight vegetable oil. Among
them, blending with diesel and oxygenate, namely alcohol addition to
form a ternary blend is selected and explored in this study. Among the
various alcohols, higher order alcohols (based on carbon content) are
gaining much attention due to their higher cetane number and calorific
value compared to lower order alcohols like methanol and ethanol for
CI engines. Another major classification of alcohol is based on the po-
sition of the OH (hydroxyl) group in their molecular structure, namely
aliphatic and aromatic. In aliphatic alcohol, OH group is bonded to
saturated carbon atom and generally, its structure is a straight chain.
Aromatic alcohol, on the other hand, has the OH group bonded to
aromatic benzene ring (aromatic carbon atom).
Aliphatic alcohol, namely 1-pentanol is taken for this study; 1-
pentanol has five carbon atoms and is classified as a higher order al-
cohol. 1-Pentanol requires less energy input for production compared to
other higher alcohols [14]. The improved blend stability with higher
calorific value and cetane number of 1-pentanol extends its application
as fuel [15]. While the current method of production is from fossil fuel,
researchers are working on the production of 1-pentanol from fer-
mentation process to achieve yet another renewable fuel [16]. In-
vestigation/Analysis of 1-pentanol as fuel with diesel, biodiesel and its
blends in CI engine has been undertaken by various researchers
[17–23].
Yilmaz and Atmanli [17] blended 1-pentanol with diesel at various
blend ratios to determine the engine characteristics at different load
conditions. 1-Pentanol was added 5, 10, 20, 25 and 35% by volume
with diesel and all the blends were tested in the CI engine. They noted
that low calorific value and cetane number of 1-pentanol reduced the
brake thermal efficiency with higher fuel consumption. However, due
to the high latent heat of vaporization, NOx emissions were reduced.
They also observed that CO emissions were reduced with slightly higher
HC emissions. It is noteworthy that the effect on performance and
emission improved/reduced with an increase in 1-pentanol blends. Si-
valakshmi and Balusamy [18] blended various alcohols including 1-
pentanol with neem oil (straight vegetable oil) in a single cylinder CI
engine at different load conditions. The alcohol proportions were 5%,
10%, 15% and 20% by volume for all the alcohol blends with neem oil.
The blend ratio was limited to 20% to avoid knocking. They observed
that brake thermal efficiency improved with increase in blend ratio of
alcohols. With respect to emissions, NOx and smoke emissions were
found to have reduced with neem oil and n-pentanol combination with
marginal improvement in HC and CO emissions. Li et al. [19] compared
the effect of n-pentanol addition with diesel and diesel-biodiesel com-
bination on performance, emission and combustion characteristics in a
single cylinder CI engine at different load conditions. They observed
that addition of n-pentanol showed shorter combustion duration and
higher heat release rate during the main combustion phase. Also, higher
thermal efficiency with improved fuel economy was observed with n-
pentanol addition in the blend. They observed that while HC and CO
emissions were reduced at higher engine loads it was bound to be
higher at lower engine loads. They noted that NOx emissions increased
at higher loads and was lower compared to base fuels at lower load
conditions. The authors stated that, with reference to NOx emissions,
positive effects like high latent heat of vaporization and negative effects
like low cetane number and presence of oxygen in n-pentanol coun-
teracted each other and may be reason for variable NOx emissions at
low and high load conditions.
In another research work, Atmanli [20] blended diesel and 1-pen-
tanol with hazelnut oil and tested it in a CI engine at different load
conditions. The blend ratio of 1-pentanol was limited to 10% by vo-
lume; they observed reduced cetane number for the blend. To improve
the cetane number, 2-ethylhexyl nitrate (EHN) was added at 500, 1000
and 2000 ppm concentration with the blends which improved the ce-
tane number by 4.65%, 12.69% and 21.09% respectively. The results
showed that the blend of diesel-hazelnut oil-1-pentanol with EHN re-
sulted in a significant reduction in fuel consumption and NOx emis-
sions. Higher alcohol addition also improved the brake thermal effi-
ciency, as reported in a few studies [21–23]. With reference to NOx
emissions, few studies showed higher NOx emissions [19–21] while
other studies showed reduced NOx emissions [17,18,22,23] with n-
pentanol addition compared to base fuels. These studies showed that n-
pentanol blend concentration and cetane number of the blend play a
major role in NOx formation and hence the results are not consistent in
all the studies. This is also evident from an earlier review article based
on use of higher alcohol fuels [24].
Aromatic alcohol, namely benzyl alcohol is taken for the purpose of
this study. Benzyl alcohol has seven carbon atoms and is hence classi-
fied as a higher order alcohol. Benzyl alcohol can be produced naturally
from Lignin by hydrolysis method and is found in a variety of essential
oils including jasmine and hyacinth [16]. It has higher calorific value
and cetane number compared to 1-pentanol. The effect of benzyl al-
cohol in diesel engines has been studied by a few researchers [25,26].
Zhou et al. [25] investigated NOx-soot tradeoffand fuel efficiency of
various aromatic oxygenates, namely anisole, benzyl alcohol and 2-
phenyl ethanol blended with diesel in a heavy-duty engine. The blended
oxygen concentration for all the three diesel blends was 2.59% by wt.
Nomenclature
B20 Simarouba oil (20%) + Diesel (80%)
B40 Simarouba oil (40%) + Diesel (60%)
P 1-pentanol
Bn Benzyl alcohol
TDC Top dead centre
BP Brake power
BTE Brake thermal efficiency
BSEC Brake specific energy consumption
CA Crank angle
EGT Exhaust gas temperature
NOx Oxides of nitrogen
CO
2
Carbon dioxide
CO Carbon monoxide
HC Hydrocarbon
V. Mathan Raj et al. Fuel 234 (2018) 934–943
935
They observed that all the three aromatic oxygenates had similar ca-
lorific value and cetane number, but differed in the position of the
hydroxyl group with the aromatic ring. All the three oxygenates were
derived from low-cost biomass, namely Lignin. They observed that all
oxygenates improved NOx-soot tradeoffand maximum improvement
was observed with benzyl alcohol as the OH group was further away
from the ring. Extending this study, Zhou et al. [26] added EGR with all
the three oxygenate blends to improve the NOx-soot tradeofffurther.
The combustion behavior was also investigated in this research. They
observed that EGR played a key role in improving the NOx-soot tradeoff
further. They concluded that benzyl alcohol blend was the best, con-
sidering performance parameters with and without EGR.
1.2. Objective of the study
The literature review shows that Simarouba glauca is a promising
energy crop that can produce viable biodiesel feedstock, it is widely
available and an excellent choice to replace diesel in a CI engine. All the
available research works focused on converting vegetable oil to bio-
diesel through transesterification. The effect of neat Simarouba glauca
oil or its blends with diesel has not been studied in literature thus far.
Poor combustion characteristics caused by neat vegetable oil might be
the reason for the lack of earlier studies. In the current research study
the authors have limited the biofuel blend with diesel to B20 and B40 to
avoid the operational problems. However, to improve the performance,
the authors have added two oxygenates, namely 1-pentanol (aliphatic)
and benzyl alcohol (aromatic). Earlier studies show that 1-pentanol aids
in simultaneously reducing NOx and smoke emissions. Benzyl alcohol
also has similar characteristics as 1-pentanol. While few studies have
been reported in ternary blending of 1-pentanol, no research work has
so far been carried out utilizing benzyl alcohol in the ternary blend.
Hence, in the current research study 5% and 10% of both 1-pentanol
and benzyl alcohol are added with B20 and B40 blend. The effect of
oxygenate addition on performance, emission and combustion char-
acteristics is studied at different load conditions. The novelty of this
work is to identify a novel oxygenate additive to improve the perfor-
mance of biofuel-diesel blend to reduce the high cost associated with
necessary transesterification of biofuels.
2. Test fuels
Simarouba glauca biofuel was procured from a local oil vendor in
Chennai, India. 1-Pentanol and benzyl alcohol were procured from M/s.
Sigma-Aldrich. The properties of the biofuel were tested based on ASTM
standards and the results are shown in Table 1. It was observed that
Simarouba oil has higher viscosity and density with lower calorific
value and hence operation in diesel engine as sole fuel poses combus-
tion, operational and long-term/continuous operation problems. How-
ever, cetane number of Simarouba oil is comparable with diesel and
hence blending low cetane fuels like alcohol will not affect its cold
starting and combustion. Biofuel was blended with diesel in the pro-
portion of 20% and 40% by volume, called as B20 and B40 respectively.
The blend was limited to B40 to avoid injector choking. The properties
of B20 and B40 are shown in Tables 2 and 3 respectively. The properties
of 1-pentanol and benzyl alcohol can be seen from Table 1. It is ob-
served that both 1-pentanol and benzyl alcohol have low viscosity and
cetane number. The molecular structure of both 1-pentanol and benzyl
alcohol shows the position of hydroxyl group. 1-Pentanol is a straight
chain and classified as aliphatic alcohol; benzyl alcohol has OH group
bonded with the aromatic benzene ring and is hence classified as
Table 1
Properties of Diesel, Simarouba oil, 1-pentanol and benzyl alcohol.
Properties Diesel fuel Simarouba oil 1-pentanol Benzyl alcohol ASTM standard
Structure –– –
Kinematic viscosity, cST @ 40 °C 3.6 34.9 2.89 5.6 D445
Density @ 15 °C, g/cm
3
0.840 0.963 0.815 0.980 D1298
Lower Heating value kJ/kg 42,700 32,500 34,500 34,650 D240
Cetane index 45–55 42 20 29 D976
Flash point, °C 74 231 49 93 D93
Table 2
Properties of B20 and its blends with alcohol.
Properties B20 B20 + P5 B20 + P10 B20 + Bn5 B20 + Bn10
Kinematic viscosity, cST @ 40 °C 9.9 9.5 9.2 9.7 9.4
Density @ 15 °C, g/cm
3
0.865 0.862 0.860 0.870 0.876
Lower Heating value kJ/kg 40,660 40,352 40,044 40,360 40,059
Cetane index 50 49 47 49 48
Flash point, °C 105 103 100 105 104
Table 3
Properties of B40 and its blends with alcohol.
Properties B40 B40 + P5 B40 + P10 B40 + Bn5 B40 + Bn10
Kinematic viscosity, cST @ 40 °C 16.1 15.5 14.8 15.6 15.1
Density @ 15 °C, g/cm
3
0.889 0.885 0.881 0.893 0.898
Lower Heating value kJ/kg 38,620 38,414 38,208 38,421 38,223
Cetane index 48 47 45 47 46
Flash point, °C 137 132 128 134 132
V. Mathan Raj et al. Fuel 234 (2018) 934–943
936
aromatic alcohol. B20 and B40 were blended with 5% and 10% of both
1-pentanol and benzyl alcohol to form the blends B20 + P5,
B20 + P10, B20 + Bn5, B20 + Bn10, B40 + P5, B40 + P10,
B40 + Bn5 and B40 + Bn10. The blend ratio of both the alcohols was
limited to 5 and 10% considering the overall cost of the fuel blends. The
blends were prepared by splash blending technique and it is found that
all the fuel blends were fully miscible and stable during testing. The
prepared samples show no phase separation even after 48 h.
3. Test engine
All the experiments were done in a Kirloskar make, single cylinder,
naturally aspirated, water-cooled type, four-stroke, direct injection
diesel engine at a constant speed of 1500 rpm and at rated power output
of 5.2 kW. The technical specifications are shown in Table 4 and the
schematic diagram of the experimental setup is illustrated in Fig. 1. The
engine was coupled with eddy-current dynamometer with an electronic
exciter for measuring and varying the load. Fuel consumption is mea-
sured on volumetric basis using a burette and stop watch. The exhaust
gas temperature was measured using a K-type thermocouple connected
to the digital display unit. The gaseous emissions, namely HC, NOx, CO
2
and CO emissions were measured using AVL Digas 444 model analyzer
which works on the principle of non-dispersive infrared (NDIR). Smoke
opacity was measured using AVL 437C model Opacimeter working
based on light extinction method. The gas analyzers were calibrated
before starting the experimental work. The in-cylinder pressure was
measured using Kistler make pressure transducer connected to a
Table 4
Engine Specifications.
Make and Model Kirloskar TV1
Engine Type Single Cylinder, Water cooled, direct injection,
constant speed
Bore (mm) 87.5
Stroke (mm) 110
Compression Ratio 17.5:1
Rated power @ 1500 rpm 5.2 kW
Injection Pressure (bar) 200
Injection timing 23°bTDC
Fig. 1. Schematic representation of experimental setup.
Table 5
Uncertainty of various instruments and parameters.
Measurement Accuracy % Uncertainty Measurement technique
Load ± 0.1 kg ± 0.2 Strain gauge type load
cell
Speed ± 10 rpm ± 0.1 Magnetic pickup type
Burette Fuel
measurement
± 0.1 cc ± 1 Volumetric
measurement
Time ± 0.1 sec ± 0.2 Manual stop watch
Manometer ± 1 mm ± 1 Principle of balancing
column of liquid
CO ± 0.02% ± 0.2 NDIR principle
HC ± 20 ppm ± 0.2 NDIR principle
CO
2
± 0.03% ± 0.15 NDIR principle
NO ± 10 ppm ± 1 Electrochemical
measurement
Smoke ± 1% opacity ± 1 Opacimeter
EGT indicator ± 1 °C ± 0.15 K-type thermocouple
Pressure pickup ± 0.5 bar ± 1 Piezoelectric sensor
Crank angle ± 1° ± 0.2 Magnetic pickup type
Table 6
Uncertainty of various parameters.
Parameters % uncertainty
Brake power ± 0.22
Brake thermal efficiency ± 1.04
Brake specific energy consumption ± 1.04
CO
2
emission ± 1.45
NO emission ± 1.75
Smoke opacity ± 1
HC emissions ± 1.45
CO emission ± 1.45
V. Mathan Raj et al. Fuel 234 (2018) 934–943
937
computer based data acquisition system. The crank angle is measured
using an encoder placed in the flywheel. The combustion analysis was
done using ‘Engine Soft’software to obtain various combustion para-
meters like in-cylinder pressure, heat release rate, ignition delay and
combustion duration. All the measurements were done for 100 cycles
and the average is taken for analysis to reduce cycle-to-cycle variations.
The accuracy of the equipment used for this research work is shown in
Table 5. In the current study, all the tests were performed at a constant
engine speed of 1500 rpm from lower to higher loads, corresponding to
the brake power (BP) of 1.3 kW, 2.6 kW, 3.9 kW and 5.2 kW. The fuel
injection timing was kept at 23°bTDC and a constant injection pressure
of 200 bar is maintained throughout the experiment. All the tests were
conducted at steady state condition without modifying the test engine.
All measurements were repeated for five times and the average value
was used for determining the derived parameters. Initially, the engine
was run with diesel for 15 min to attain warm-up condition. The
emission parameters like HC, NOx were measured in terms of ppm and
CO were measured in terms of % volume which was converted to g/
kWh based on number of moles. The uncertainty analysis of all the
performance and emission parameters are done based on the square
root method and displayed in Table 6.
4. Results and discussions
Performance, emission and combustion characteristics of the engine
are analyzed at various load conditions, from 0 to 100% of full rated
capacity. Diesel, B20, B40 and its blends with 1-pentanol and benzyl
alcohol are tested in the CI engine, and the results are compared with
the base fuel.
4.1. Combustion parameters
Engine combustion parameters like in-cylinder pressure, heat re-
lease rate, ignition delay and combustion duration for diesel, B20, B40
and alcohol blends with B20 and B40 at 100% load are discussed in this
section.
4.1.1. In-cylinder pressure
In-cylinder pressure inside the combustion chamber is controlled by
the amount of fuel prepared and burnt in instantaneous combustion.
Fig. 2 shows the variation of in-cylinder pressure with crank angle for
diesel, B20, B40 and alcohol blends with B20 and B40 at 100% load.
Peak pressure for B20 and B40 is less compared to diesel; this may be
due to inferior mixture formation during the delay period causing a
reduced instantaneous combustion and subsequent lower peak pres-
sure. The reduction in in-cylinder pressure depends on increase in
biofuel proportion. Peak pressure for diesel, B20, and B40 are 68.5 bar,
65.7 bar and 61.8 bar; it is also observed that peak pressure occurrence
is delayed with an increase in biofuel quantity [11]. Peak pressure for
B20 and B40 shifted 2°CA and 5°CA respectively from peak pressure of
diesel fuel. Addition of 1-pentanol and benzyl alcohol, improved com-
bustion compared to B20 and B40. Peak pressure for B20 + P5,
B20 + P10, B20 + Bn5 and B20 + Bn10 are 69.4 bar, 71.9 bar, 72 bar
and 76.9 bar respectively and for B40 + P5, B40 + P10, B40 + Bn5 and
B40 + Bn10 are 66.2 bar, 68.6 bar, 67.8 bar and 69.9 bar respectively.
It is seen that addition of 1-pentanol, improved combustion due to
improved atomization rate and faster combustion process. However,
increase in 1-pentanol blend delayed the occurrence of peak pressure
due to lower cetane number of 1-pentanol [14]. Benzyl alcohol addition
showed superior combustion compared to 1-pentanol addition with
both B20 and B40. This is due to the position of hydroxyl group leading
to improved free radical propagation. It is also noted that increase in
benzyl alcohol increased peak pressure with both B20 and B40. The
tests also show that, due to higher cetane number of benzyl alcohol,
peak pressure occurred early compared to 1-pentanol.
4.1.2. Heat release rate
Heat release rate is obtained from in-cylinder pressure data based on
the first law of thermodynamics. Fig. 3 shows the variation of heat
release rate corresponding to crank angle for diesel, B20, B40 and al-
cohol blends with B20 and B40. It is observed that compared to diesel,
peak heat release rate for B20 and B40 is less. The possible reason is due
to less fuel prepared for instantaneous combustion despite more ex-
tended delay period as a result of poor physical properties of biofuel,
viz. density, viscosity, and calorific value [20]. It is also observed that
the combustion is slower with B20 and B40 which extends the com-
bustion, resulting in more wastage of power. This is evident from the
lower BTE and higher EGT, as discussed previously. With the addition
of 1-pentanol and benzyl alcohol, peak heat release is improved due to
improved combustion as a result of improved fuel properties with al-
cohol addition. Also, the longer ignition delay period causes more fuel
accumulation, and faster combustion rate of both alcohols is also worth
noting [14,17].Compared to 1-pentanol, peak heat release rate for
benzyl alcohol is higher and also occurs slightly early. Aromatic alcohol
has higher evaporation rate and combined with the position of the OH
group in benzyl alcohol aids in faster combustion rate leading to higher
peak heat release rate. This shows that combustion efficiency is im-
proved with benzyl alcohol addition compared to 1-pentanol and this
phenomenon is increased with increase in the proportion of benzyl al-
cohol. This improvement shows that more energy produced is trans-
formed into work with less energy loss compared to B20 and B40.
300 320 340 360 380 400 420
0
10
20
30
40
50
60
70
80
In-cylinder pressure (bar)
Crank angle (deg)
Diesel
B20
B20 + P5
B20 + P10
B20 + Bn5
B20 + Bn10
300 320 340 360 380 400 420
0
10
20
30
40
50
60
70
In-cylinder pressure (bar)
Crank angle (deg)
Diesel
B40
B40 + P5
B40 + P10
B40 + Bn5
B40 + Bn10
Fig. 2. Variation of in-cylinder pressure with crank angle at 100% load.
V. Mathan Raj et al. Fuel 234 (2018) 934–943
938
6
7
8
9
10
1
/
10
100%