ISSN : 2249-5762 (Online) | ISSN : 2249-5770 (Print)
IJRMET Vol. 4, Issue Spl - 1, Nov 2013- April 2014
Study of Combustion and Vibration on DI -Diesel Engine
Fueled With Rice Bran Methyl Ester Injection
and Ethanol Carburetion
1
Dr. K.Rambabu, 2M. Sri Rama Murthy, 3M.Ramji, 4Dr. B.V.Appa Rao
Dept. of ME, Sir C.R.R.College of Engineering, Eluru, AP, India
Dept. of Marine Engg., AU College of Engg., Andhra University, Visakhapatnam, AP, India
1,2,3
4
Abstract
In this present paper experimental study results of combustion
and vibration on DI -Diesel engine fueled with rice bran methyl
ester injection and ethanol carburetion are presented. The Present
research trend is to replace Petro-diesel by renewable alternative
fuels in view of fast depletion of petroleum reserves and to reduce
the exhaust emissions from engines. In this study biodiesel (Rice
bran methyl ester) is used as a total replacement to Petro-diesel.
It is proved that biodiesel reduces the engine emissions but for
the Nitric Oxide emission which is emitted more than that when
neat diesel fuel is implemented. This is the main reason to turn
our attention to dual fuel operation with rice bran methyl ester
injection and ethanol carburetion to reduce even Nitric Oxide
emission (NO) also. Detail study of combustion performance,
engine performance, exhaust emission and vibration analysis on
DI -Diesel engine fueled with Rice Bran Methyl Ester Injection
and Ethanol Carburetion is carried out. Betterment is observed
at a particular ethanol mass flow rate. Experimental study results
of combustion and vibration analysis part only discussed in this
present paper.
Keywords
Rice Bran Methyl Ester, Ethanol, Carburetion, Combustion,
Vibration
I. Introduction
The increasing industrialization and motorization of the world
has led to a steep rise in the demand of petroleum-based fuels.
Petroleum-based fuels are obtained from limited reserves. These
finite reserves are highly concentrated in certain regions of the
world. Therefore, those countries not having these resources are
facing energy/foreign exchange crisis, mainly due to the import of
crude petroleum. Hence, it is necessary to look for alternative fuels
which can be produced from resources available locally within
the country such as alcohol, biodiesel, vegetable oils etc. Ethanol
is also an attractive alternative fuel because it is a renewable
bio-based resource and it is oxygenated, thereby providing the
potential to reduce particulate emissions in compression-ignition
engines. Biodiesel is methyl or ethyl ester of fatty acid made from
virgin or used vegetable oils (both edible and non-edible) and
animal fat. The main resources for biodiesel production can be
non-edible oils obtained from plant species such as Jatropha curcas
(Ratanjyot), Pongamia pinnata (Karanj), Calophyllum inophyllum
(Nagchampa), Hevea brasiliensis (Rubber) and edible oils like
rice bran,soya bean etc
Ethanol is a poor fuel for a diesel engine because of its low ignition
quality or cetane value. It is to be emphasized that a high octane
fuel (a virtue for a petrol engine), necessarily has a low cetane
value (a curse for a diesel engine). The flammability results of
ethanol are higher than gasoline or diesel. More ethanol vapor has
to be produced and mixed with air before a flammable mixture is
produced. This factor together with ethanol’s high latent heat of
98
evaporation , low vapor pressure and high boiling point , demands
more energy to produce ethanol air mixture flammable. The main
research in diesel alcohol technology is to find ways and means
to force alcohol to ignite by compression in the diesel engine
recognizing these fuel characteristics.
Anhydrous ethanol can be blended with diesel fuel, but several
problems remain to be solved before diesohol can be considered
a practical alternative [1-2]. The problems can be avoided by
keeping the ethanol in a separate tank and injecting it into the
air stream of the engine. This technique is called vaporization. It
has been shown that it is possible to replace up to 60% of diesel
fuel, using the vaporization method [3]. Adding a carburetor has
been suggested as a relatively inexpensive way of vaporizing
ethanol into a naturally aspirated diesel engine [4] when ethanol
is carbureted into a naturally aspirated diesel engine, energy is
required to vaporize the ethanol. An air pre-heater could supply
the energy needed to achieve the complete evaporation. Though
several researchers have reported the vaporization of ethanol
in higher horse- power engines [5, 6] there is no information
on the use of vaporized ethanol in low horse- power stationary
engines. Since these types of engines are commonly used in the
agricultural and transport sectors of developing countries, there
is a need to study their performance using vaporized ethanol.
The first objective of the study reported in the paper [7] was to
investigate the effect of fuelling a constant speed low horsepower
diesel engine with vaporized ethanol. The second objective was
to study the effect of preheating the ethanol air mixture on engine
performance.
In this study, the diesel fuel is replaced with neat Rice Bran Methyl
Ester (RBME). Heated Ethyl alcohol is carbureted at the suction
end through a bifurcated suction arrangement. This attempt is made
after surveying the previous work done on alcohol carburetion.
Several vegetable oils are being produced in India however; it is
desirable to give priority to that oil, which is not being used for
human consumption in practice. Among vegetable oils rice bran
oil can be used as CI engine fuel because rice is one of major crops
cultivated in India. In spite of an annual production of 91 MMT
rice grain with a theoretical potential of 1.2 MMT rice bran oil,
the estimated production was only 0.7 MMT in 2004-05 (Solvent
Extractors Association of India). Extra 0.5 MMT rice bran oil
may be available for 10 percent replacement of diesel used in
agriculture sector of India.
The exhaust gas temperature of the engine on all the blends of
methyl ester of rice bran oil-diesel was found to be lower than
that of diesel at rated load. The emission of carbon monoxide
from the engine was found to be lower on all the blends of methyl
ester of rice bran oil-diesel compared to diesel at rated load. The
emission of un burnt hydrocarbon from the engine at higher loads
was found to be more on all the fuel blends as compared to diesel.
The emission of NOx from the engine found to be higher on the
all fuel blends as compared to diesel [8].
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IJRMET Vol. 4, Issue Spl - 1, Nov 2013 - April 2014
ISSN : 2249-5762 (Online) | ISSN : 2249-5770 (Print)
A. RBME: Injection & Preheated Ethanol Carburetion
In this study, dual fuel operation is adapted with RBME injection
and preheated ethanol carburetion. Attention is bestowed upon
the reduction of HC, NO, and CO emissions and the same is
successfully achieved with the preheated ethanol carburetion of
70.17mg/sec. Vibration on the engine cylinder in three directions
and on the foundation is measured and analyzed to elicit information
about the nature of combustion. Experimental study results of
combustion and vibration analysis part is presented.
II. Experimental Setup
The experimental setup consists of the following equipment:
• Single cylinder engine loaded with eddy current dynamometer
• Engine Data Logger
• Exhaust gas Analyzer
• Smoke Analyzer
• Vibration Analyzer
• Ethanol carburetor
• Electrical heating gadget with Programmable Temperature
controller for preheating the ethanol.
The schematic diagram (Fig. 1) represents the instrumentation
set up for the experiment. The Piezo electric transducer is fixed
(flush in type) to the cylinder body (with water cooling adaptor) to
record the pressure variations in the combustion chamber. Crank
angle is measured using crank angle encoder. Exact TDC position
is identified by the valve timing diagram and fixed with a sleek
mark on the fly wheel and the same is used as a reference point
for the encoder with respect to which the signals of crank angle
will be transmitted to the data logger. The data logger synthesizes
the two signals and finally the data is presented in the form of a
graph on the computer using C7112 software.
Vibration accelerometer is mounted on the cylinder head, preferably
on the bolt connecting the head and the cylinder to record the engine
vibrations using DC-11 data logger which directly gives the spectral
data in the form of FFT. This FFT data recorded is collected by OnTime window based software designed by e-predict Inc., Argentina.
The Time waveforms are obtained on the cylinder head by DC-11
in the OFF-ROUT mode and are presented in graphic form by
Vast-an doss based software, designed by VAST, Inc., Russi.
The amount of Ethanol is regulated by the throttle opening of the
carburetor and the engine performance was tested at six different
throttle openings. Various higher proportions of Ethanol is being
tried to eliminate the knocking condition. Different mass flow rates
of Ethanol viz. 195.90 mg/sec, 137.20 mg/sec, 106.90 mg/sec,
70.17 mg/sec, 48.45 mg/sec, 23.14 mg/sec were implemented at
the six different throttle openings as mentioned earlier. 195.90 mg/
sec mass flow rate is threshold flow value above which knocking
becomes intensive (which is identified with sudden power loss
and vibration severity) and hence higher mass flow rates above
this percentage were discarded. Throttle opening more than this is
forfeited. Experimentation is carried out at various engine loads
by means of eddy current dynamometer. Engine performance
data is acquired to investigate engine performance along with the
engine pollution parameters
Fig. 2: Diesel Engine Test Rig With Ethanol Carburetion at the
Bifurcated Air Inlet With the Preheating Arrangement
III. Engine and Fuel Specifications
A. Engine Details
Table 1. Specifications of Kirlosker Diesel Engine
Rated Horse power:
5 hp (3.73 kW)
Rated Speed:
1500rpm
No of Strokes:
4
Mode of Injection and injection Direct Injection,200 kgf/
pressure
cm2
No of Cylinders: 1
Stroke
110 mm
Bore
87.5 mm
Compression ratio
16.5
Fig.1: Schematic Diagram of Experimentation
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IJRMET Vol. 4, Issue Spl - 1, Nov 2013- April 2014
B. Fuel Properties
Table 2: Properties of Diesel, Rice Bran Methyl Ester and
Ethanol
Diesel
Rice
bran
methyl
ester
Ethanol
Density @ 330c (kg/
m3)
833
868.6
783.2
2
Lower calorific value
(kJ/kg)
43000
38552
26855
3
Cetane number
51
63.8
8
4
Kinematic viscosity
@ 330c (cSt)
2.58
3.57
1.2
5
Conradson’s Carbon
Residue (Wt %)
0.1
0.35
-----
6
Stoichometric air
–fuel ratio
15
13.8
9
Latent heat of
evaporation (kJ/kg)
250
------
840
Flash point (0c)
Fire point (0c)
68
72
185
196
-----------
S.No
Name of the oil
sample →
↓Characteristics
1
8
9
IV. Combustion Heat Release Rate calculations
Pressure crank angle history is obtained from the engine data
logger for the engine load defined. After obtaining the data for
combustion cycle, the net heat release rate is calculated based
on the first law of thermodynamics. The heat transfer from the
gases to the cylinder is computed and deducted from the gross
heat release rate to arrive at the net heat release rate which is
presented in the form of graphs.
When analyzing the internal combustion engine, the in-cylinder
pressure has always been an important experimental diagnostic
due to its direct relation to the combustion and work producing
processes. The in-cylinder pressure reflects the combustion process
involving piston work produced on the gas (due to changes in
cylinder volume), heat transfer to the chamber walls, as well as
mass flow in and out of crevice regions between the piston, rings
and cylinder liner. Thus if an accurate knowledge of how the
combustion process propagates through the combustion chamber
is desired, each of these processes must be related to the cylinder
pressure [9], so the combustion process can be distinguished. The
deduction of the effects of volume changed, heat transfer, and mass
loss on the cylinder pressure is called heat-release analysis and is
done within the framework of the first law of thermodynamics,
when the intake and exhaust valves are closed, i.e. during the
closed part of the engine cycle. The simplest approach is to regard
the cylinder contents as a single zone, whose thermodynamic
state and properties are modeled as being uniform throughout the
cylinder and represented by average values. No spatial variations
are considered, so the model is said to be zero-dimensional. Models
for heat transfer and crevice effects can easily be included. Krieger
R B, and Borman G L, Gatowski and A. Ramesh have contributed
a lot to develop the Heat release rate models in internal combustion
engines. In this thesis, the Gatowski model has been chosen to
evaluate the heat release rate in the combustion chamber with neat
diesel and neat biodiesel as well as with dual fuel combinations.
In this single zone model, the film coefficient to calculate heat
100
transfer and other important temperatures are deemed unchanged
with the dual fuel operation.
V. Result Discussion & Conclusion
Low temperature and high velocity combustion is aimed at in this
experimentation by implementing ethanol as one of the fuels in a
dual fuel system. The second fuel which is injected is the rice bran
methyl ester. Performance of this dual fuel system is compared
with the replaced diesel fuel. The latent heat of vaporization
of ethanol is 840 kJ/kg, which is around three and half times
to that of the Petro-diesel (Diesel’s latent heat of vaporization
is 250 kJ/kg). Combustion at lower temperature will be taking
place because of higher latent heat of vaporization of ethanol.
In this experimentation, preheated ethanol (preheating ensures
evaporation in the carburetor) is carbureted at the suction end in
a bifurcated passage with varying mass flow rates depending on
the throttle opening of the carburetor and the rice bran methyl
ester is injected through the existing nozzle employed for diesel
injection. Since the ethanol flow rate is constant depending on the
throttle opening, the rice bran methyl ester consumption quantity
increases at higher loads on the engine decreasing the ethanol
percentage in the dual fuel operation. The engine employed is
DI diesel engine with a horse power rating of 5 hp and rated
speed 1500 rpm with nozzle opening pressure of 200 bar. The
stoichiometric air fuel ratio of ethanol is 9 where as that of diesel is
15. Ethanol needs lesser air for complete combustion because it is
oxygenated fuel with energy density 15.8 MJ/m3 of fuel. (Diesel’s
energy density is 35.7 MJ/m3).The cetane number of ethanol is
8 and that of RBME is 63.8. Hence implementation of ethanol
increases the delay period and thus helps in reducing the exhaust
pollution. Ethanol’s lower calorific value is 26,855 kJ/kg and that
of rice bran methyl ester is 38,552 kJ/kg. Ethanol’s presence in the
dual fuel operation cannot promise power enhancement but acts
like an additive to reduce exhaust emissions at certain ethanol’s
equivalence ratio. There is an incidence of emission reduction
with the specific ethanol flow rate of 70.17 mg/sec including NO,
and the most possible assumption is that the RBME combustion is
effectively controlled by the ethanol’s burning in the composition.
Ethanol’s boiling point is 780 C and hence it is to be preheated to
in between 400 C to 500 C before being sent into the carburetor
to ensure partial dry vapor to charge the cylinder. There is no
specific design change of the engine to effect this kind of dual
fuel operation, but it is essential to provide retrofits like carburetor
and the ethanol heating arrangement.
A. Combustion Performance
1. Combustion Analysis ( P-θ Signatures & Derived Plots)
It can be observed from the pressure crank angle plots (Fig. 3 to
Fig. 10), the start of combustion is delayed as the ethanol flow
rate is increasing. Anyhow, lowering the load on the engine delays
the start of combustion because of greater share of ethanol in
the fuel mixture. At higher shares of ethanol, because of lower
cetane number of ethanol the delay period increases. At lower
loads up to 3/4th load, the higher HC release indicates incomplete
combustion with the increase of ethanol. This is the reason for
the decrease of peak pressure at high ethanol flow rates. At the
full load, when compared to RBME flow rate, the proportion of
ethanol is smaller and even at highest flow rate of ethanol 195.90
mg/sec, effective utilization of ethanol has taken place and leading
to peak pressure rise. As ethanol flow decreases the peak pressure
plummets downed matching with the condition when neat RBME
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is implemented (Fig. 12). Ethanol mass shares for six throttle positions of carburetor and for five loads are shown in Table 3.
Table 3: Ethanol Mass Shares for Various Throttle Positions of Carburetor
Ethanol Mass Share (%)
Combination 1
(Throttle
position 1)
Combination 2
(Throttle
position 2)
Combination 3
(Throttle
position 3)
Combination 4
(Throttle
position 4)
Combination 5
(Throttle
position 5)
Combination 6
(Throttle position 6)
195.90 mg/sec
137.20 mg/sec
106.90 mg/sec
70.17 mg/sec
48.45 mg/sec
23.14 mg/sec
No load
67.58%
59.07%
51.73%
40.68%
32.23%
18.30%
1/4th load
66.02%
55.70%
44.63%
34.22%
25.78%
13.41%
Half load
59.08%
48.36%
37.74%
28.36%
21.00%
10.72%
3/4th load
50.17%
39.35%
31.10%
22.51%
16.17%
8.09%
Full load
42.71%
32.85%
26.50%
18.82%
12.93%
6.49%
2. Combustion Pressure Plots
It can be observed that as the load on the engine is increasing the
RBME consumption quantity is increasing. Since the quantity
of ethanol flow depends on the throttle opening, for a defined
throttle opening the amount of ethanol flow into the engine remains
constant. Hence at higher loads, the ratio of ethanol to RBME
ratio (ethanol mass share (%)) is reducing and results to decrease
of the ignition delay (Fig. 3 to Fig. 8). It is obvious that the
cetane number of RBME (63.8) is more than that of ethanol’s (8).
The heat release rate curves also envisage the same phenomena
supporting the ignition delay change as explained above. Peak
pressures are complying more with the ethanol flow ratio in the
total fuel. In general, the peak pressures are increasing with load.
But with the lower ethanol ratios at high loads the peak pressures
are plummeting marginally, finally converge to the performance
of neat RBME.
Pressure plot of RBME+137.20mg/sec Ethanol Flow
90
80
Pressure in Cylinder (bar)
Ethanol
mass flow
rate
70
60
50
40
30
20
10
0
-10
320
330
No Load
60
50
40
30
20
10
0
-10
No Load
360
370
380
Crank Angle(deg)
1/4th Load
Half Load
390
400
410
380
390
400
410
420
Half Load
3/4th Load
Full Load
80
420
70
60
50
40
30
20
10
0
-10
320
330
340
350
360
370
380
390
400
410
420
Crank Angle(deg)
3/4th Load
Fig. 3: Pressure Plot of RBME+195.90 mg /sec
w w w. i j r m e t. c o m
1/4th Load
Pressure in Cylinder (bar)
Pressure in Cylinder (bar)
70
350
370
Pressure plot of RBME+106.90 mg/sec Ethanol Flow
80
340
360
Fig. 4. Pressure Plot of BME+137.20 mg/sec Ethanol Flow Rate.
Ethanol Flow Rate.
90
330
350
Crank Angle(deg)
Pressure plot of RBME+195.90mg/sec Ethanol Flow
320
340
Full Load
No Load
1/4th Load
Half Load
3/4th Load
Full Load
Fig. 5: Pressure Plot of RBME+106.90 mg/sec
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IJRMET Vol. 4, Issue Spl - 1, Nov 2013- April 2014
Pressure plot of RBME+70.17mg/sec Ethanol Flow
Pressure plot of Diesel
80
80
Pressure in Cylinder (bar)
70
70
Pressure in Cylinder (bar)
60
50
40
30
20
10
0
320
330
No Load
-10
350
360
370
380
Crank Angle(deg)
340
1/4th Load
Half Load
390
400
410
60
50
40
30
20
10
420
0
-10
3/4th Load
320
Full Load
Fig. 6. Pressure plot of RBME+70.17 mg/sec Ethanol Flow
Rate
Pressure plot of RBME+48.45mg/sec Ethanol Flow
330
340
350
360
370
380
390
400
410
420
Crank Angle(deg)
No Load
1/4th Load
Half Load
3/4th Load
Full Load
Fig. 10: Pressure Plots of Diesel Fuel
80
Pressure in Cylinder (bar)
70
Pressure plot at Full Load
60
40
30
20
10
0
-10
320
330
340
350
360
370
380
390
400
410
420
Crank Angle(deg)
No Load
1/4th Load
90
80
70
60
50
40
30
20
10
0
-10
Pressure in Cylinder (bar)
50
320
Half Load
3/4th Load
Full Load
Fig. 7: Pressure Plot of RBME+48.45 mg/sec
330
340
350
360
370
380
390
Crank Angle(deg)
400
410
420
RBME+195.90mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+106.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
RBME
DIESEL
Fig. 11: Pressure Plots of All Fuel Combinations at Full Load
Pressure plot of RBME+23.14mg/sec Ethanol Flow
Pressure in Cylinder (bar)
80
70
Load Vs Peak Pressure
60
50
40
90
30
80
10
70
0
-10
320
330
No Load
340
350
360
370
380
390
Crank Angle(deg)
1/4th Load
Half Load
400
3/4th Load
410
420
Full Load
Fig. 8: Pressure Plot of RBME+23.14 mg/sec Ethanol Flow Rate.
Ethanol Flow Rate
Peak Pressure (bar)
20
40
30
20
0
80
70
Pressure in Cylinder (bar)
50
10
Pressure plot of RBME
60
50
40
30
60
No
loa
d
1/4
th
loa
d
Ha
lf l
oa
d
3/4
th
loa
d
Fu
l l lo
ad
RBME+195.90mg/sec Ethanol
RBME+106.90mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
RBME
RBME+ 23.14mg/sec Ethanol
DIESEL
Fig. 12: Peak Pressure Plots of Fuel Combinations at All Loads
20
10
0
-10
320
330
340
350
360
370
380
390
400
410
420
Crank Angle(deg)
No Load
1/4th Load
Half Load
3/4th Load
Full Load
Fig. 9: Pressure Plots of RBME Fuel
102
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Crank Angle Vs Net Heat Release Rate For
RBME+137.20mg/sec Ethanol Flow
Load Vs D. Pressure
80
Net Heat Release Rate(J/deg)
5
4
70
60
Pressure plot of RBME+195.90mg/sec Ethanol Flow
50
90
80
40
Pressure in Cylinder (bar)
D. Pressure (bar/deg)
6
3
2
1
0
No
loa
d
1/4
th
loa
d
Ha
lf l
oa
d
3/4
th
loa
d
Fu
l l lo
70
30
60
50
20
40
10
30
200
10
330
ad
RBME+195.90mg/sec Ethanol
RBME+106.90mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
RBME
RBME+ 23.14mg/sec Ethanol
DIESEL
320
340
330
340
No
Load
No Load
1. Net Heat Release Plots
Same in the cumulative heat release curves also (Fig. 23 to Fig.
31). The knocking in the engine can be palpable by the sudden
changes in the cumulative heat release rate curves. There is a
hump development in the trajectory of the cumulative heat release
rate which subsided finally to minimum with the reduction of
ethanol.
Crank Angle Vs Net Heat Release Rate For
RBME+195.90mg/sec
EthanolEthanol
Flow Flow
Pressure
plot of RBME+195.90mg/sec
Pressure
in Cylinder
(bar)
Net
Heat Release
Rate (J/deg)
50%
Load
Half Load
400
410
75%
3/4th Load
Load
410
420
Full
Full Load
Load
60
Pressure plot of50RBME+195.90mg/sec Ethanol Flow
90
40
80
70
30
60
50
20
40
10
30
20
0
10
330
320
340
330
No
No Load
Load
340
350
350
-100
-10
360
370
380
360
370
380
Crank
Angle
(deg)
Crank Angle(deg)
25%
1/4th Load
Load
50%
Load
Half Load
390
390
400
400
410
75%
Load
3/4th Load
410
420
Full
Load
Full Load
80
Pressure plot of RBME+195.90mg/sec Ethanol Flow
Net Heat Release Rate(J/deg)
70
90
40
30
30
20
20
10
10
00
-10
-10
360
360
370370 380 380390 390
400
Crank
(deg)
Crank Angle
Angle(deg)
50% Load
Half Load
75% Load
3/4th Load
400
410
420410
80
60
70
50
60
40
50
Pressure in Cylinder (bar)
50
40
30
40
30
20
20
10
10
00
330
320
330340 340 350
350
Full Load
Full Load
No Load
Load
No
Fig. 14. Net HRR plots of the combination of RBME +195.90
mg/sec ethanol flow rate.
w w w. i j r m e t. c o m
25%
1/4th Load
Load
400
Crank Angle Vs Net Heat Release Rate For
RBME+70.17mg/sec Ethanol Flow
60
50
1/4th Load
390
390
70
70
60
No Load
380
380
80
80
70
25% Load
370
370
Fig. 16: Net HRR Plots of the Combination of RBME +106.90
mg/sec Ethanol Flow Rate
80
90
No Load
360
Crank
Angle (deg)
Crank
Angle(deg)
Crank Angle Vs Net Heat Release Rate For
RBME+106.90mg/sec Ethanol Flow
Pressure
Cylinder
(bar) Rate(J/deg)
Net in
Heat
Release
B. Heat Release Rate Analysis
As load increases RBME consumption increases and its
combustion taking leading part in the combustion and the delay
period decreases by 50 of crank revolution. With the increase of
ethanol quantity, the maximum net heat release rate increased
(Fig.14 to Fig. 22) reflecting
330 340 340 350
350
350
Fig. 15: Net HRR Plots of the Combination of RBME +137.20
mg/sec Ethanol Flow Rate
Fig. 13: Differential Pressure Plots of Fuel Combinations at All
Loads
330
320
-10
0
350 -10 360
-10
-10
360
360
370
370
380380 390 390
400
CrankAngle
Angle(deg)
Crank
(deg)
25%
1/4th Load
Load
50%
Load
Half Load
75%
3/4th Load
Load
400
410
410
420
Full
Full Load
Load
Fig. 17: Net HRR Plots of the Combination of RBME +70.17 mg/
sec Ethanol Flow Rate
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Crank Angle Vs Net Heat Release Rate For
RBME+48.45mg/sec Ethanol Flow
Crank Angle Vs Net Heat Release Rate For Diesel
Pressure
in Cylinder
(bar) Rate(J/deg)
Net Heat
Release
80
80
Pressure
in Cylinder
(bar) Rate(J/deg)
Net Heat
Release
70
60
Pressure plot of 50
RBME+195.90mg/sec Ethanol Flow
90
80
40
70
30
60
50
20
40
30
10
20
0
10
330 330
320
340340
No Load
0
-10
-10
350
360
350
360
1/4th Load
No Load
370 380 380390
370
Crank Angle
Angle(deg)
Crank
(deg)
Half Load
25% Load
390
400
400
410
3/4th Load
50% Load
410
420
Full Load
60
Pressure plot of RBME+195.90mg/sec Ethanol Flow
50
90
80
40
70
30
60
50
20
40
10
30
20
0
10
-10
0
330
320
Full Load
75% Load
Fig. 18. Net HRR Plots of the Combination of RBME +48.45 mg/
sec Ethanol Flow Rate
70
340
330
350
340
No Load
No
Load
350
-10 360
360
370
370
380
380
390
Crank
Angle (deg)
Crank
Angle(deg)
1/4th Load
Load
25%
Half Load
Load
50%
390
400
400
410
3/4thLoad
Load
75%
Fig. 21: Net HRR Plots of Diesel Fuel
410
420
FullLoad
Load
Full
Crank Angle Vs Net Heat Release Rate at Full Load
80
80
Pressure
in Cylinder
(bar) Rate(J/deg)
Net Heat
Release
70
Net Heat Release Rate(J/deg)
Crank Angle Vs Net Heat Release Rate For
RBME+23.14mg/sec Ethanol Flow
70
60
Pressure plot of RBME+195.90mg/sec Ethanol Flow
90
50
80
40
70
30
60
50
20
60
50
40
30
20
10
0
330
40
340
-10
360
350
200
10
330
320
-10
0
350 -10 360
340
330
340
No
No Load
Load
350
360
370
370
380
380
390
Crank
Angle (deg)
Crank
Angle(deg)
25%
1/4th Load
Load
50%
Load
Half Load
390
400
400
410
75%
3/4th Load
Load
410
420
Full
Full Load
Load
Fig. 19: Net HRR Plots of the Combination of RBME +23.14 mg/
sec Ethanol Flow Rate
70
60
Pressure plot of RBME+195.90mg/sec Ethanol Flow
50
90
80
Pressure in Cylinder (bar)
40
70
30
60
50
20
40
RBME+106.90mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
RBME
Diesel
Fig. 22: Net HRR Plots of all Fuel Combinations at Full Load
2. Cumulative Heat Release Plots
Crank Angle Vs Cumulative Heat Release Rate For
RBME+195.90mg/sec Ethanol Flow
250
Pressure plot of RBME+195.90mg/sec Ethanol Flow
200
150
100
No
Load
No Load
340
350
360
370
370
380
380
Crank
Angle (deg)
Crank
Angle(deg)
25%
1/4th Load
Load
50%
Load
Half Load
390
390
400
75%
3/4thLoad
Load
400
410
410
420
Full
FullLoad
Load
90
80
70
60
50
40
30
50
320
330
10
330
410
RBME+137.20mg/sec Ethanol
320
200
320
400
RBME+ 70.17mg/sec Ethanol
10
30
340
390
RBME+195.90mg/sec Ethanol
Pressure
in Cylinder
(bar)Release
Cumulative
Heat
Rate (J/deg)
Net Heat Release Rate(J/deg)
80
330
380
300
Crank Angle Vs Net Heat Release Rate For
RBME
-10
0
350 -10 360
370
Crank Angle (deg)
10
30
No
No Load
Load
340
340
20
10
0 0
-10
360
350
360
380
370
400
380
Angle(deg)
CrankCrank
Angle(deg)
1/4th
Load
25% Load
Half Load
50%
Load
390
420
400
3/4th
Load
75% Load
440
410
460
420
Full Load
Load
Full
Fig. 23: Cumulative HRR Plots of the Combination of RBME
+195.90 mg/sec Ethanol Flow Rate
Fig. 20: Net HRR Plots of RBME Fuel
104
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ISSN : 2249-5762 (Online) | ISSN : 2249-5770 (Print)
Crank Angle Vs Cumulative Heat Release Rate For
RBME+48.45 mg/sec Ethanol Flow
Crank Angle Vs Cumulative Heat Release Rate For
RBME+137.20mg/secEthanol Flow
Pressure plot
300of RBME+195.90mg/sec Ethanol Flow
90
90
200 80
70
150 60
50
100 40
30
NoLoad
Load
No
350
360
380
370
400
380
Crank
Angle(deg)
Crank
Angle(deg)
25% Load
Load
1/4th
50% Load
Load
Half
390
420
400
440
410
75% Load
3/4th
Load
460
420
Pressure
in Cylinder
(bar)ReleaseRate
Cumulative
Heat
(J/deg)
300
320
60
50
40
330
340
No Load
Load
No
350
360
380
370
400
380
Crank
Angle(deg)
Crank
Angle(deg)
50%
HalfLoad
Load
390
420
400
440
410
75%
3/4thLoad
Load
460
420
Full
Load
Full
Load
Fig. 25: Cumulative HRR Plots of the Combination of RBME
+106.90 mg/sec Ethanol Flow Rate
330
340
340
No
No Load
Load
40
30
20
10
360
380
370
400
380
Crank
Angle(deg)
Crank
Angle(deg)
50%
Half Load
Load
420
390
400
75%
3/4thLoad
Load
440
410
460
420
Full
FullLoad
Load
Fig. 26: Cumulative HRR Plots of the Combination of RBME
+70.17 mg/sec Ethanol Flow Rate
w w w. i j r m e t. c o m
150
100
410
440
3/4thLoad
Load
75%
420
460
FullLoad
Load
Full
70
60
50
40
30
20
10
50
340
340
0
0 -10
350
360 360
370
380
380
400
Crank
Angle(deg)
Crank
Angle(deg)
25% Load
50% Load
1/4th Load
300
250
200
150
100
50
Half Load
390 420 400
410
440
75% Load
420
460
Full Load
3/4th Load
Full Load
340
340
RBME
80
70
60
50
40
30
20
10
0
0
-10
360 360
350
380370
400
380
Crank
Angle(deg)
Crank
Angle(deg)
1/4thLoad
Load
25%
300
50
25%
1/4thLoad
Load
HalfLoad
Load
50%
390 420 400
HalfLoad
Load
50%
390 420 400
440
410
3/4thLoad
Load
75%
460
420
FullLoad
Load
Full
Crank Angle Vs Cumulative Heat Release Rate For
60
0
-10
360
350
380
400
Diesel
Pressure plot of RBME+195.90mg/sec
Ethanol Flow
70
0
320
200
Pressure
inHeat
Cylinder
(bar)
Cumulative
ReleaseRate
(J/deg)
Pressure
in Cylinder
Cumulative
Heat(bar)
Release
Rate (J/deg)
320
90
80
50
370
380
Fig. 29: Cumulative HRR Plots of RBME Fuel
Pressure plot of RBME+195.90mg/sec Ethanol Flow
100
250
No
No Load
Load
300
150
1/4thLoad
Load
25%
300
320 320 330
Crank Angle Vs Cumulative Heat Release Rate For
RBME+70.17 mg/sec Ethanol Flow
200
360
Crank
Angle(deg)
Crank
Angle(deg)
90
20
25%
1/4thLoad
Load
250
0
0
350
360
Crank Angle
Vs RBME+195.90mg/sec
Cumulative Heat Release
Rate For
Pressure
plot of
Ethanol
Flow
30
10
340
10
Fig. 28: Cumulative HRR Plots of the Combination of RBME
+23.14 mg/sec Ethanol Flow Rate
70
0
0
-10
360
340
340
No Load
No
Load
80
320
20
Crank Angle Vs Cumulative Heat Release Rate For
90
RBME+23.14 mg/sec Ethanol Flow
80
320 320 330
250
Pressure plot of RBME+195.90mg/sec Ethanol Flow
200 90
50
50
30
Pressure plot of RBME+195.90mg/sec Ethanol Flow
Crank Angle Vs Cumulative Heat Release Rate For
RBME+106.90mg/sec Ethanol Flow
100
100
40
Fig. 27: Cumulative HRR Plots of the Combination of RBME
+48.45 mg/sec Ethanol Flow Rate
Full
Load
Full Load
Fig. 24: Cumulative HRR Plots of the Combination. of RBME
+137.20 mg/sec Ethanol Flow Rate
150
60
50
150
No
No Load
Load
0 0
-10
360
PressureHeat
in Cylinder
(bar)
Cumulative
ReleaseRate
(J/deg)
340
340
70
200
320 320 330
10
330
80
-10
50 20
320
320
Pressure inHeat
Cylinder
(bar)
Cumulative
ReleaseRate
(J/deg)
250
Pressure plot of RBME+195.90mg/sec Ethanol Flow
250
PressureHeat
in Cylinder
(bar)
Cumulative
ReleaseRate
(J/deg)
Pressure in Cylinder (bar)
Cumulative Heat ReleaseRate
(J/deg)
300
320 320 330
No
No Load
Load
90
250
80
200
60
150
100
50
70
50
40
30
20
10
0
340
340
0 -10
360 360
350
380
370
400
380
Crank
Angle(deg)
Crank
Angle(deg)
25%
1/4thLoad
Load
50%
HalfLoad
Load
390 420 400
75%
3/4thLoad
Load
440
410
460
420
Full
FullLoad
Load
Fig. 30: Cumulative HRR Plots of Diesel Fuel
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Crank Angle Vs Cumulative Heat Release Rate at Full Load
Cumulative Heat ReleaseRate
(J/deg)
300
250
200
150
100
50
320
0
360
340
380
400
Crank Angle(deg)
420
440
460
RBME+195.90mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+106.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
RBME
DIESEL
Fig. 31: Cumulative HRR Plots of All Fuel Combinations at Full
Load
C. Exhaust Gas Temperature
It is observed that the exhaust gas temperature is decreasing
with increasing ethanol flow rate at any load (Fig. 32).This is
because of high latent heat of vaporization of ethanol and lower
combustion temperatures. From no load to full load, the exhaust
gas temperature are observed to be 40C, 210C, 280C, 400C, and
290C less with 70.17 mg/sec of ethanol flow rate combination
in comparison with RBME. This is also agreeing with the rise
in the thermal efficiency which is indicative of better torque
conversion.
100
95
94
96
96
95
96
100
98
150
124
117
114
119
122
122
140
129
181
173
200
149
147
145
153
155
156
Exhaust gas Temperature ( o C)
250
245
244
246
252
264
265
281
278
235
227
Load Vs Exhaust gas Temperature
184
192
178
195
207
207
300
Table 4: Sequence of Combination Points in 3-D Spectrum of
Vibration
50
0
No load
1/4th load Half load
RBME+195.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME
RBME+137.20mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
DIESEL
3/4th load
Full load
RBME+106.90mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
Fig. 32: Load Verses Exhaust Gas Temperature
D. Vibration Analysis
Vibration of the cylinder head in three directions and that of the
foundation frame are measured for comparison and to verify
the combustion smoothness. The rice bran oil methyl ester with
different proportions of ethanol (ethyl alcohol) has been tested on
the engine to verify the vibration intensity, which can be attributed
to the smoothness/roughness of operation of the engine with the
particular combination.
The vibration measured in vertical direction gives appropriate
measure of the combustion propensity in the case of vertical
cylinder engine. The ethanol mix emanated higher vibration
levels where as neat RBME produced lower levels. Anyhow, the
combination consisting of 70.17 mg/sec for ethanol equivalence
ratio 0.054 has shown consistent performance with lower levels of
vibration on the cylinder and on the foundation. Considerable drop
in the vibration is observed in the high frequency regions with
106
the decrease of ethanol quantity in combination with the RBME.
The amplitude levels in the 3-D graphs in the chosen frequency
regions for the above said combination with 70.17 mg/sec ethanol
flow rate are indicative of the vibration reducing nature. Table. 4
indicates the six combinations with ethanol flow, neat RBME and
neat diesel in sequence on which the vibration is recorded.
Figs. 37 to 42 envisage higher amplitudes of vibration for the
ethanol flow rate of 195.90 mg/sec measured in all three directions
of the cylinder at full load. On contrary, at no load, the same flow
rate is reducing the vibration amplitudes (Fig. 33 to Fig. 36).There
are rare occasions where in the engine is kept running at no load.
Hence higher flow rate of ethanol (195.90 mg/sec) may not be
encouraging. This 195.90 mg/sec of ethanol flow as shown in
fig. 40 produced high frequency vibration at 17888 Hz with an
amplitude of 0.2319 g on the cylinder in a direction in line to the
crank and there is a tradeoff between low frequency vibrations to
high frequency side. Normal engine knocking can be attributed with
this ethanol flow rate. Same is the case experienced in vibration
measurement inline to crank on the cylinder head at 3/4th load..
Figures 43 and 44 envisage high frequency excitation i.e. 18,192
Hz with amplitude of 0.256 g. In the high rigidity planes like in
line to crank direction and vertical on the same maximum flow
rate at no load condition produced minimum spectrum average
when measured vertical on the cylinder head. But figures 53 and 54
display high frequency vibration at 18608 Hz, with an amplitude
of nearly 0.2 g indicating knocking condition, for even a flow rate
of 106.90 mg/sec. The average spectrum values for neat RBME
operation produced minimum vibration levels on the cylinder head
and on the foundation and any ethanol mix raises engine vibration.
Ethanol flow rate of 106.90 mg/sec generates almost lowest levels
of vibration on the cylinder head (Fig. 33 to Fig. 36), but there
is trade off in the amplitude levels when it comes to foundation
vibration which is maximum at all loads. The mode of vibration
from the top of the engine to the foundation is changing when
the ethanol content is changing bringing change in the position
of nodes in vertical vibration mode.
Point No
Combination
3
Combination 1 RBME+195.90 mg/sec ethanol
4
Combination 2 RBME+137.20 mg/sec ethanol
1
Combination 3 RBME+106.90 mg/sec ethanol
2
Combination 4 RBME+ 70.17 mg/sec ethanol
5
Combination 5 RBME+ 48.45 mg/sec ethanol
6
Combination 6 RBME+ 23.14 mg/sec ethanol
7
Neat RBME
Neat RBME
8
Neat diesel
Neat diesel
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RBME + ethanol flow (mg/sec)
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2
0
Half load
RBME+195.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
5.152
3/4th load
3.128
3.928
2.805
3.318
2.898
3.112
2.612
3.788
1/4th load
No load
2.519
2.869
3.208
3.105
3.751
3.095
2.753
3.063
2.567
2.703
3.416
2.636
3.61
3.003
3.261
4
2.058
1.755
2.374
2.573
2.361
2.486
2.225
2.236
Average Spectrum Value (g)
6
3.407
2.417
2.117
2.461
2.502
2.592
2.62
2.35
Load Vs Average Spectrum value
(vertical on cylinder head)
Full load
RBME+106.90mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
2
1/4th load
Half load
3.273
3.706
No load
2.226
2.794
2.579
3.416
2.587
4.231
3
1.751
2.658
2.54
2.924
2.601
2.779
2.496
2.456
4
2.058
2.591
2.016
2.309
1.61
2.565
3.214
2.759
5
2.802
3.339
2.815
2.883
2.366
2.944
2.605
3.072
Load Vs Average Spectrum value
(inline to crank on cylinder head)
2.296
2.235
2.048
2.464
3.174
1.661
2.259
3.33
Average Spectrum Value (g)
Fig. 33: Average Spectrum Values When Vibration Measured in Vertical Direction on Cylinder Head
1
0
RBME+195.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
3/4th load
Full load
RBME+106.90mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
Fig. 34: Average Spectrum Values When Vibration Measured Inline to Crank on Cylinder Head
1/4th load
Half load
3/4th load
4.253
No load
3.019
2.649
3.133
3.19
2.774
3.49
3.387
3.692
3.999
2
2.966
3.267
3.2
2.274
3.129
2.923
3.392
3.857
3
2.698
2.676
2.66
2.037
3.289
2.785
4.018
3.474
4
3.36
3.052
2.696
2.651
3.133
3.377
(perpendicular to crank on cylinder head)
5
2.681
3.014
2.041
1.901
2.745
3.316
3.341
3.084
Average Spectrum Value (g)
Load Vs Average Spectrum value
1
0
RBME+195.90mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME
RBME+137.20mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
DIESEL
Full load
RBME+106.90mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
Fig. 35: Average Spectrum Values When Vibration Measured Perpendicular to Crank on Cylinder Head
w w w. i j r m e t. c o m
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IJRMET Vol. 4, Issue Spl - 1, Nov 2013- April 2014
1
0
No load
1/4th load
Half load
RBME+195.90mg/sec Ethanol
RBME+137.20mg/sec Ethanol
RBME+ 70.17mg/sec Ethanol
RBME+ 48.45mg/sec Ethanol
Fig. 36: Average Spectrum Values When Vibration Measured on Foundation
Fig. 37: 3-D Plot in the Frequency Range of 0-300Hz. Recorded
Perpendicular to the Crank on Engine Cylinder When Running
at Full Load
Fig. 39: 3-D Plot in the Frequency Range of 17000-18000Hz.
Recorded Inline to the Crank on Engine Cylinder When Running
at Full Load
108
1.246
1.696
1.775
2.142
3/4th load
2.762
2.149
2.907
2.145
2.875
1.533
1.647
2.43
3.207
2.303
1.419
2.041
1.428
1.517
2.356
1.268
1.175
1.102
1.189
1.819
2
1.328
1.16
3
1.389
1.343
2.108
1.283
0.9445
1.145
1.271
1.548
Average Spectrum Value
(g)
4
2.876
3.312
Load Vs Average Spectrum value
(on foundation)
1.357
1.961
1.518
1.524
5
Full load
RBME+106.90mg/sec Ethanol
RBME+ 23.14mg/sec Ethanol
Fig. 38: FFT Spectrum at the Cursor Location 48Hz for
Combination1, RBME+195.90 mg/sec Ethanol Flow Rate,
Recorded Perpendicular to the Crank on the Engine Cylinder
When Running at Full Load
Fig. 40: FFT Spectrum at the Cursor Location 17888 Hz for
Combination1, RBME+195.90 mg/sec Ethanol Flow Rate,
Recorded Inline to the Crank on the Engine Cylinder When
Running at Full Load
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Fig. 41: 3-D Plot in the Frequency Range of 600-1000Hz.
Recorded Vertical on the Engine Cylinder Head When Running
at Full Load
Fig. 43: 3-D Plot in the Frequency Range of 17000-18500Hz.
Recorded Inline to the Crank on the Engine Cylinder When
Running at 3/4th load
Fig. 45: 3-D Plot in the Frequency Range of 18000-19000Hz.
Recorded Vertical on the Engine Cylinder Head When Running
at Half Load
w w w. i j r m e t. c o m
Fig. 42: FFT Spectrum at the Cursor Location 656Hz for
Combination1, RBME+195.90 mg/sec Ethanol Flow Rate,
Recorded Vertical on Engine Cylinder Head When Running at
Full Load
Fig. 44: FFT Spectrum at the Cursor Location 18192 Hz for
Combination1, RBME + 195.90 mg/sec Ethanol Flow Rate,
Recorded Inline to the Crank on the Engine Cylinder When
Running at 3/4th Load
Fig. 46: FFT Spectrum at the Cursor Location 18864Hz for
Combination1, RBME + 195.90 mg/sec Ethanol Flow Rate,
Recorded Vertical on the Engine Cylinder Head When Running
at Half Load
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Fig. 47: 3-D Plot in the Frequency Range of 17000-18000Hz.
Recorded Inline to the Crank on the Engine Cylinder When
Running at 1/4th Load
Fig. 49: 3-D Plot in the Frequency Range of 4000-5000Hz.
Recorded in Line to the Crank on the Engine Cylinder Head When
Running at no Load
Fig. 51: 3-D Plot in the Frequency Range of 950-1300Hz. Recorded
Vertical on the Engine Foundation When Running at no Load
110
Fig. 48: FFT Spectrum at the Cursor Location 17808 Hz for
Combination2, RBME + 137.20 mg/sec Ethanol Flow Rate,
Recorded Inline to the Crank on the Engine Cylinder When
Running at 1/4th Load
Fig. 50: FFT Spectrum at the Cursor Location 4736Hz for
Combination5, RBME + 48.45 mg/sec Ethanol Flow Rate,
Recorded Inline to the Crank on the Engine Cylinder Head When
Running at no Load
Fig. 52: FFT Spectrum at the Cursor Location 1136Hz for
Combination 4, RBME + 70.17 mg/sec Ethanol Flow Rate,
Recorded Vertical on the Engine Foundation When Running at
no Load
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IJRMET Vol. 4, Issue Spl - 1, Nov 2013 - April 2014
ISSN : 2249-5762 (Online) | ISSN : 2249-5770 (Print)
Fig. 53: 3-D Plot in the Frequency Range of 18000-19000Hz.
Recorded Vertical on the Engine Cylinder Head When Running
at no Load
[2] Boruff P. A., Schwab A. W., Goering C. E., Pryde, E. H.,
"Evaluation of diesel fuel -ethanol micro emulsions",
Transactions of the ASAE, 1982, 25(1), pp. 47-53.
[3] Goering C.E, Crowell TJ, Griffith DR, Jarrett MW, Savage
LD. Compression-ignition, flexible-fuel engine. Transactions
of the ASAE, 1992, 35(2), pp. 423-428.
[4] Goering, C. E. and Wood, D. R.,"Over fuelling a diesel engine
with carbureted ethanol", Transactions of the ASAE, 1982,
25(3), pp. 576-580.
[5] Chaplin, J., Janius, R. B.,"Ethanol fumigation of a compression
ignition engine using advanced injection of diesel fuel",
Transactions of the ASAE, 1987, 30(3), pp. 610-614.
[6] Sarkkinen, K.,"Alcohol for automobiles", Indian Auto, 1997,
7(4), pp. 20-21.
[7] E.A.AJAV, Bachchan Singh, T. K. Bhattacharya, "Performance
of a Stationary Diesel Engine using Vapourized Ethanol as
Supplementary Fuel”, Biomass and Bioenergy, Vol. 15, No.
6, pp. 493-502, 1998.
[8] Jayant Singh, T. N. Mishra, T. K. Bhattacharya, M. P.
Singh,"Emission Characteristics of Methyl Ester of Rice Bran
Oil as Fuel in Compression Ignition Engine", International
Journal of Chemical and Biomolecular Engineering, Vol. 1,
No. 2, pp. 63-67
[9] K. M. Chun, J. B. Heywood,“Estimating heat-release and
mass-of-mixture burned from spark-ignition engine pressure
data”, Combustion Sci. and Tech., Vol. 54, pp. 133–143,
1987.
Fig. 54: FFT Spectrum at the Cursor Location 18608 Hz for
Combination3, RBME + 106.90 mg/sec Ethanol Flow Rate,
Recorded Vertical on Engine Cylinder Head When Running at
no Load
VI. Conclusion
1. This is an attempt to replace the diesel fuel with alternate
oxygenated fuels. In the normal operation with the neat
RBME, there is reduction in ignition delay because of its
higher cetane number. With the addition of ethanol along
with the RBME, delay period has increased.
2. Peak pressures are complying more with the ethanol flow ratio
in the total fuel. In general, the peak pressures are increasing
with load. But with the lower ethanol ratios at high loads the
peak pressures are plummeting marginally, finally converge
to the performance of neat RBME.
3. It is observed that the exhaust gas temperature is decreasing
with increasing ethanol flow rate at any load.
4. Knocking is predicted at the highest throttle opening i.e.
195.90 mg/sec flow rate of ethanol and the engine power is
also reduced as consequent of that.
5. Vibration amplitudes at the ethanol flow rate of 70.17 mg/sec
are minimal and hence implementation of this proportion of
ethanol in the dual fuel operation is mostly recommended in
view of several benefits associated with this combination.
References
[1] Wrage, K. E., Goering, C. E.,"Technical feasibility of
diesohol", Agricultural Engineering, 1979, 60(10), pp. 3436.
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