International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT) - 2016
The Effect of Advanced Ignition Timing on
Ethanol-Gasoline Blended Spark Ignition Engine
B.V. Lande1
Research Scholar,
Mechanical Engg. Deptt.,
BDCOE, Sewagram (India)
bv_lande@rediffmail.com
Abstract— Ethanol requires higher activation energy for
ignition and so it takes more time to ignite. Spark timing has
to be advanced for reducing ignition delay period and
misfiring of engine. Increasing number of coils and voltage to
increase spark temperature, solve the problem of activation
energy required for ethanol and ignition delay. This study was
aimed to identify the effect of variable ignition timing on
engine performance and exhaust emission of a spark ignition
engine. A single cylinder four stroke engine with eddy current
dynamometer and artificial ignition system used to investigate
the effect of variable ignition timing on performance and
exhaust emissions. The test engine was operated with different
blend of ethanol-gasoline (E5, E10, E15 and E20). The results
have shown considerable performance improvement in brake
thermal efficiency and decrease in break specific fuel
consumption as well as reduction in HC, CO emission.
Keywords— Ethanol, Performance, Compression ratio,
Ignition timing.
I.
INTRODUCTION
Ethanol has become significant fuel for replacement of
gasoline in transportation section. Ethanol with higher octane
number requires earlier ignition timing than gasoline fuel.
Ignition timing in a spark ignition internal combustion engine
is the process of setting the angle relative to piston position
and crankshaft angular velocity that a spark will occur in the
combustion chamber near the end of compression stroke. The
need for advancing the timing of the spark is because fuel does
not
completely burn the instant the spark fires, the
combustion gases takes a period of time to expand and the
angular or rotational speed of the engine can lengthen or
shorten the time frame in which the burning and expansion
should occur. In a vast majority of cases, the angle will be
described as a certain angle advanced before top dead centre
(BTDC). Advancing the spark BTDC means that the spark is
energized prior to the point where the combustion chamber
reaches its minimum size. Since the purpose of power stroke
in the engine is to force the combustion chamber to expand.
Spark occurring after top dead centre (ATDC) are usually
978-1-4673-9939-5/16/$31.00 ©2016 IEEE
Dr. Suhas Kongre2
Head of Mechanical Engg. Deptt.,
A. S. Polytechnic,
Wardha.(India)
kongresuhas@gmail.com
counterproductive (Producing wasted spark, back fire, engine
knock etc.) unless there is need for a supplemental or
continuing spark prior to exhaust stroke. Setting the correct
ignition timing is crucial in the performance of an engine. The
ignition timing affect many variables including engine life,
fuel economy and engine power. Modern engine that are
controlled by an engine control unit use a computer to control
the timing throughout the engines rpm range. Older engines
that use mechanical spark distributors rely on inertia (by using
rotating weights and springs) and manifold vacuum in order to
set the ignition timing throughout the engines rpm and load
range.
Timing advance refers to the number of degree before
top dead centre (BTDC) that the spark will ignite the air fuel
mixture in the combustion chamber during the compression
stroke. Retarded timing can be defined as changing the timing
so that the fuel injection happens later than the manufactured
specified time. Timing advance is required because it takes
time to burnt the air-fuel mixture, If the air fuel mixture is
ignited at the correct time, maximum pressure in the cylinder
will occur. The objective of research work is to investigate the
effect of advanced Ignition Timing on performance of engine
and exhaust emissions.
II.
•
LITERATURE REVIEW
Ethanol effects on engine performance
Several studies have been conducted on the usage of ethanol
and ethanol – gasoline blends as fuel in SI engines.
In recent years several researchers have been carried
out the influence of using ethanol – gasoline blend on the
performance of spark Ignition engines. Shane Curtis [1]
investigated the engine performance and pollutant emission of
an SI engine using ethanol-gasoline blends (E10 and E20).
Their experimental result indicated that, without
modification in air –fuel system, E10 can be used.
The 10% ethanol blend produces similar fuel
conversion efficiency, brake work and bsfc to pure
gasoline.CO and HC emission decreases with E10.
Hsieh [2] investigated the engine performance and pollutant
emission of an SI engine by using ethanol-gasoline blends
(E0, E5, E10, E20 and E30). Their experimental result
indicated that torque output and fuel consumption slightly
increase when using ethanol-gasoline blended fuel. CO and
HC emission decrease dramatically as a result of the leaning
effect. When ethanol is added to the blended fuel, it can
provide more oxygen for the combustion process called
Leaning effect. H.Bayraktar [3] investigated the effect of
ethanol addition (from 0% to 12%) to gasoline on an SI engine
performance and exhaust emissions. The brake power and
brake thermal efficiency increased with increasing ethanol
amount in the blended fuel as a result of improved combustion
and HC,CO emission decreased. Al Hassan [4] investigated
the effect of ethanol-unleaded gasoline blends on performance
and emissions. The unleaded gasoline blended with ethanol to
prepare 10 test samples ranging from 0 to 25% ethanol with an
increment of 2.5%. Ethanol addition resulted in an increased
in brake power, brake thermal efficiency, volumetric
efficiency and fuel consumption by about 8.3%,9%,7% and
5.7% respectively. Experimental study of exhaust emission
and performance analysis of multi cylinder SI engine when
methanol used as an additive studied by M.V.Mallikarjun[5]
Experimentation was carried out on four cylinder SI engine by
adding methanol in different percentage. During
experimentation some slight modification with various sub
system of engine under different load condition and for
various percentage of methanol blends(0-15). It is observed
that there is an increase in octane number and improvement in
brake thermal efficiency. Ibrahim Thamer Nazzal [6]
investigated that the effects of alcohol blends on the
performance of a typical spark ignition engine and compared
engine performance by using 12% ethanol-88% gasoline ,12%
methanol -88% gasoline and 6% ethanol-6%methanol88%gasoline with gasoline fuel. The engine performance was
measured at variety of engine operating conditions. The result
are presented in terms of speed and their effect are indicated
that when ethanol gasoline blended fuel is used, break power
of engine slightly increased and break thermal efficiency also
increased.
•
Compression ratio and Ignition Timing effect on
engine performance
Experiments in variable compression ratio single cylinder
engine fuelled by blends of gasoline and ethanol with different
concentrations have been performed by Celik[7] . Celik
attempted to determine a suitable ethanol-gasoline blend for
spark-ignition engine. Compression ratio varying from 6:1 to
10:1 and using blend of gasoline with ethanol concentration of
0% (Eo), 25% (E25) ,50% (E50) ,75% (E75) and 100%
(E100). Engine output power and HC emission were
optimized with compression ratio 6:1 and 2000 rev/min. Using
E50 as a fuel, with increasing ethanol content in the fuel,
specific fuel consumption increased, while CO, CO2 and NOx
emission level were decreased. In the work by Yucesu[8]
compression ratios from 8:1 to 13:1 and fuel blends with up to
60% of ethanol content in gasoline [E60] were tested. For
different engine speeds, the torque produced was increased
with higher compression ratio and ethanol concentration.
Specific fuel consumption was decreased with increasing
compression ratio but increased with increasing ethanol
content in the fuel. Lower exhaust gas temperatures were
obtained for higher ethanol concentration in the fuel blend, as
a result of ethanol flame speed being faster in comparison with
gasoline. Lower CO and HC emissions level were obtained for
higher ethanol concentration in the fuel blend. Ceviz and
Yuksel[9] investigated the effect of ethanol gasoline blends
on cyclic cylinder pressure variation in a spark ignition
engine. Fuel blend with up to 20% of ethanol content were
used in the investigation. The fuel blend containing 10%
ethanol {E10] produced the lowest variation of indicted mean
effective pressure for fifty consecutive cycles. E10 fuel blend
also produce lowest CO and HC emission levels. Topgul[10]
investigated the effects of ethanol-gasoline blend [
E0,E10,E20,E40,E60] and ignition timing on performance and
emission. The experimental result showed that the brake
torque slightly increased and CO and HC emission decrease
when ethanol –gasoline blend was used. James Sczybist,
Mathew foster [11] investigate optimization methodologies for
E85 in an effort to minimize the full penalty compared to
gasoline. The specific goal of this study was to examine the
high-load knock limit of ethanol blends at three different
compression ratio and also investigate optimization
methodologies for E85 in an effort to minimize the fuel
consumption compared to gasoline. The fuel properties of
ethanol in particular the high octane number and high latent
heat of vaporization provide opportunities for higher
efficiency with ethanol that are not currently exploited in
FFVs. Investigation was carried out on single cylinder engine
equipped with turbocharger. Numerous modification were
made to the cylinder head, engine block and intake manifold
to allow the engine to accommodate the HVA system. They
also modify the valve opening system, valve closing system
and valve lift can be controlled independently for each of the
four valves. There was improvement in thermal efficiency &
engine power when ethanol content increases. Compatibility
with knock-prone fuels can be maintained at high CR with the
use EJVC or LIVC strategies. These strategies reduce
effective CR, which reduces the likelihood of knock. When an
EIVC or LIVC control strategy is used to prevent knock at
high engine load, the engine output is substantially de-rated
compared to fuels that do not exhibit knock under
conventional valve timing (i.e.E85or E50). As CR increases
knock prone fuels become more derated so much so that at
CR= 12.87 the IMEP difference between E85 and RG is
nearly 33% combustion duration increases with the EIVC
control strategy, and is attributed to reduction in charge
motion. According to F.Yuksel and B.Yuksel (12) one of the
major problem for the successful application of gasolinealcohol mixture as a motor fuel is the realization of a stable
homogeneous liquid phase. To overcome this problem, authors
designed a new carburetor. Sixty percent ethanol and Forty
Percent gasoline blend was exploited to test the performance,
the fuel consumption and the exhaust emissions. Experimental
result indicate that using ethanol-gasoline blended fuel ,the
CO and HC emission decreased dramatically as a result of the
leaning effect caused by ethanol addition and CO2 emission
increased because of the improved combustion, Rodrigo
Costa, Jose R. Sodre (13) investigated the influence of
compression ratio on the performance of a spark ignition
engine fuelled by a blend of 78% gasoline 22% ethanol or
hydrous ethanol ( E100). Investigation was carried out on
1.0L, eight valve, four cylinder production engine. Engine
speed was varying from 1500 to 6500 rev/min. Three
compression ratio were investigated 10:1, 11:1 and 12:1. The
performance parameter were evaluated torque, brake mean
effective pressure, power, specific fuel consumption, thermal
efficiency, exhaust gas temperature and volumetric efficiency.
Test result showed that Engine torque, BMEP and output
power are substantially improved with increased compression
ratio at high speed for both, E22 and hydrous ethanol.
Compression ratio is a key issue for flexible fuel technology
development. The compression ratio of fuel flexible engine is
knock limited for gasoline use. Increasing compression ratio
increases exhaust temperature and decreases SFC.
Phuangwongtrakul S.( 14) studied suitable ignition timing and
fuel injection duration for Ethanol-Gasoline blended fuels
spark ignition engine. Since ethanol has lower heating value
and higher octane number than gasoline, the high supplied
torque is able to obtain by advancing the ignition timing.
However, the brake specific fuel consumption seems to
increase with the ethanol composition in ethanol-gasoline
blended fuels. The relative air/fuel ratio for maximum brake
torque is obtained in the rich burn combustion regime, which
the relative air/fuel ratio for minimum brake specific fuel
consumption is obtained in the lean burn combustion regime.
Syed Yousufuddin, Syed Nawazish Mehdi (15) studied effect
of ignition timing, equivalence ratio, and compression ratio on
the performance and emission characteristics of a variable
compression ratio of SI engine using ethanol unleaded
gasoline blends. In this study, the effects of using unleaded
gasoline and unleaded gasoline-ethanol blends on engine
performance and exhaust emissions were investigated by
varying the ignition timing and compression ratio. Based on
the experimental study, the following results were obtained:
Minimum BSFC was obtained at 11:1 compression ratio with
E0 fuel. Comparison with 9:1 compression ratio, the BSFC
decreased 9.25 %. The maximum decreasing of BSFC was
obtained with E25 at 11:1 compression ratio. The minimum
BSFC was obtained at 0.95 equivalence ratio for all test fuels
and increased depending on ethanol percentages. Blending
unleaded gasoline with ethanol increased the brake torque
when the ignition timing was retarded. Ethanol addition did
not increase the brake torque at all ignition timings at the
compression ratio of 11:1. For ignition timing of 25° CA and
over, the engine torque decreases. Advancing the ignition
timing to 29° CA caused knock occurrence with E0 fuel.
However, knock occurrence was not observed up to 35° CA
advanced ignition timing with unleaded gasoline ethanol
blends (E35 and E65). The engine torque increased with
increasing compression ratio to 11:1, the increment is about
5.72 % when compared with 9:1 compression ratio. The
variation of exhaust temperature with ignition timing at the
compression ratio of 9:1 was very similar to the variation at
the compression ratio of 11:1. Retarding the ignition timing
caused the exhaust temperature to increase. The fuels
containing high ratios of ethanol; E35 and E65 had significant
effect on the performance.
From the above literature review ,it is understood that
many of the researchers carried out their investigation for
performance and exhaust emissions of spark ignition engine
with ethanol-gasoline blend by varying compression ratio and
varying ignition timing with ethanol-gasoline blend ,there was
improvement in break thermal efficiency and reduction in
exhaust emissions. But there is no guideline available for
using optimum blend of petrol and no information about the
relation between ignition timing and blend percentage. The
aim of this research work to suggest guideline for using
suitable ethanol gasoline blend rate in terms of performance
and emissions for small engine manufacturer in India. The
other aim is to investigate experimentally the improvement of
the performance and emission by testing the engine with
suitable ethanol – gasoline blend fuel at variable ignition
timing.
III.
EXPERIMENTATION
The Experimental set up shown in fig 1 consisted of single
cylinder, four stroke water cooled petrol engine coupled to
eddy current dynamometer with the help of flexible coupling
is mounted on a centrally based frame made up of M.S.
channel. The setup has stand alone fully powder coated panel
box consisting of air box, fuel tank manometer, fuel measuring
unit, digital indicators.
The overhead cylinder head made of cast Iron is
water cooled externally & has a counter piston which helps in
varying the clearance volume. The Counter piston is actuated
by a screw rod mechanism to change clearance volume for
different compression ratios. The Compression ratio varies
from 4.5 to 9.0. Various parts of engine are shown in Fig 2
and specification in Table I and Table II. Load cell is mounted
on the end of dynamometer as the loading arm hits the load
cell which senses the load and read out the torque. K-type
thermocouples are used for measurement of various
temperatures. For measurement of exhaust emissions, five gas
analysers are used. The properties of fuel are calculated by
testing the fuel in laboratories.
Before performance, the blend of ethanol with
gasoline prepared in various proportions (like 5%, 10%,15%
and 20%) on volume basis. The engine was allowed to run
with gasoline for compression ratio 4.5. After completing the
experiment with gasoline, the experiments was conducted with
4 samples (E5,E10,E15,E20). After completing the
experiments with the first sample blend, the engine was
allowed to run for half an hour to eliminate the interference of
previous sample blend. All sample blends were tested with
same procedure for C.R (4.5). with advanced ignition timing.
The performance parameters and exhaust emissions were
recorded.
TABLE I.
Sr.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TECHNICAL DATA SPECIFICATION
Particulars
Data
Manufacturer
Model
No. of Cylinder
Cubic capacity
Bore
Stroke
Compression Ratio
Ignition System
Starting Method
Lubrication System
Carburetor
Crown ton Wheel
MK-25/ MK-40
Single cylinder
256 cc
70 mm
66.7mm
4.67
Electronic
Rope and Pulley
Splash Type
Greaves 1320 Up draught
type float system
Dry type (Foam Element)
6305/C3 25 x 62 x 17 mm
Air Cleaner
Bearings on Both
Sides
Cylinder
Fig. 2. Experimental Setup (Line Diagram)
TABLE II
Sr. No
Cast Iron BS:1452/17
ENGINE SPECIFICATIONS
1
2
3
Specifications
Horsepower(HP)
RPM( Engine Speed)
Engine Weight
Mark 25
3/3.4
3000
26 kg
4
5
6
7
8
9
10
11
12
Pumpset weight
Monoblock
Fuel
Fuel Tank Capacity
Bore Diameter
Stroke length
Connecting Rod length
Swept Volume
Compression Ratio
49 Kg
(21/2’’x 2’’)
Petrol
4.5 litres
70 mm
66.7 mm
154 mm
256 cc
2.5:1-10:1
IV. RESULT AND DISCUSSION
After Experimentation graphs are plotted between:BTHE Vs Torque
BSFC Vs Torque
CO Vs Torque
HC Vs Torque
CO2 Vs Torque
NOX VS Torque
Fig. 1.
Experimental Setup
•
Break Thermal Efficiency: - Thermal efficiency is
given by the ratio between output power and fuel
energy content, which in its turn is calculated by
product of fuel mass flow rate and low
heating value. Fig.3,4,5 shows that the graph
between brake thermal efficiency and torque for
compression ratio 4.5 with variable ignition timing
100,130 and 150. Due to advanced ignition timing,
air furl mixture get sufficient time to ignite. From
the above graph it shows that thermal efficiency
increases with increase in percentage of ethanol in
blend and also increase with advanced ignition
timing. here thermal efficiency increases with E5
and E10 compared to E0(gasoline). The maximum
brake thermal efficiency is recorded with E10.
Percentage increase in break thermal efficiency with
different blend and advanced ignition timing is
4.65%.
ethanol fuel. Fig.6,7 & 8 shows that the graph
between bsfc and torque for compression ratio 4.5
with variable ignition timing 100,130 and 150. Fuel
consumed for one kilowatt power generation in one
hour is defined as brake specific fuel consumption.
Opposite trend of graph, fuel consumption increases
with increase in load but brake specific fuel
consumption decreases with increase in load as it is
function of fuel consumption and brake power.
Fig. 6 (Ignition Timing 100 BTDC)
Fig. 3 (Ignition Timing 100 BTDC)
Fig. 7 (Ignition Timing 130 BTDC)
Fig. 4 (Ignition Timing 130 BTDC)
Fig. 8 (Ignition Timing 150 BTDC)
Emissions:-
Fig. 5 (Ignition Timing 150 BTDC)
•
Break Specific Fuel Consumption:- The fuel
consumption increases as the engine torque
increases. This behavior is attributed to the low
heating value per unit mass of the ethanol which is
distinctly lower than that of gasoline fuel. Therefore
the amount of fuel introduced into engine cylinder
for a given desired fuel has to be greater with
i) CO Emissions: - Ethanol contain an Oxygen atoms in its
basic form, it therefore can be treated as a particularly
oxidized hydrocarbon. When ethanol is added to the blended
fuel, it can be provide more oxygen for combustion process.
When ethanol containing oxygen is mixed with gasoline , the
combustion of the engines becomes better and therefore CO
emission is reduced. Fig.9,10,and 11shows that there is
decrease in the value of carbon monoxide emissions with
varying percentage of ethanol in blend. Due to advanced
ignition timing ,the process of combustion is completed. The
value of CO is decreases as compared to gasoline is15%.
Fig. 9 (Ignition Timing 100 BTDC)
Fig. 12(Ignition Timing 100 BTDC)
Fig. 10 (Ignition Timing 130 BTDC)
Fig. 13(Ignition Timing 130 BTDC)
Fig. 11 (Ignition Timing 150 BTDC)
ii) HC emissions:- Hydrocarbon is also product of incomplete
combustion of fuel. The formation of hydrocarbon is due to
lack of air supply. The results obtained for ethanol blending
are plotted against different loading condition. HC emission
indicate power loss, higher the hydrocarbon emission, higher
the power loss resulting into less brake thermal efficiency. But
with addition of ethanol, hydrocarbon emission lowered down
significantly. The emission for hydrocarbon shows declined
trend for higher loading and complete burning of fuel which
is further improved with oxygenated fuel. Fig.12,13 and
14show that the hydrocarbon emission decreases with increase
in percentage of ethanol and with increase in ignition timing.
This is due to the reduction in carbon atoms concentration in
the blended fuel and high molecular diffusivity and high
flammability which improves mixing process and combustion
efficiency.
Fig. 14(Ignition Timing 150 BTDC)
iii) CO2 Emissions:- The stochiometric air-fuel ratio of
ethanol is about 2/3 that of gasoline, hence the required
amount of air for complete combustion is lesser for ethanol.
When the engine condition goes leaner the combustion
process is more complete and the CO2 emissions get higher.
Fig.15,16 and 17 show that CO2 emission increases with
increase in percentage of ethanol and varying ignition timing.
Fig. 15(Ignition Timing 100 BTDC)
Fig. 16(Ignition Timing 130 BTDC)
Fig. 20 (Ignition Timing 150 BTDC)
V. CONCLUSION
From experimentation it is observed that ignition
timing can also be used as an alternative way for
predicting the performance of internal combustion
engines besides specific fuel consumption, specific
power output, exhaust smoke and other emissions.
1] It is concluded that break thermal efficiency
increases with advanced ignition timing and break
specific fuel consumption decreases because due to
advanced ignition timing, there is complete
combustion.
2] Carbon monoxide and hydrocarbon emission
decreased as the ignition timing was increased
because of the sufficient time available for complete
combustion.
Fig. 17(Ignition Timing 150 BTDC)
iv) NOx Emission :- As ethanol fuel also has high latent heat
of vaporization, it reduces the peak temperature inside the
cylinder .Due to complete combustion the emission of NOx
increases with varying the percentage of ethanol.Fig18,19, and
20 shows the variation of NOx emission with varying torque.
ACKNOWLEDGMENT
With immense pleasure and great respect ,I take this
opportunity to express my deep sense of gratitude towards my
project guide Dr.Suhas Kongre Associate Professor & HOD
mechanical engineering department A.S.Polytechnique
wardha for invaluable guidance throughout my work. I am vey
thankful to Prof. C.B.Kothare Principal A.S.Technology
wardha for his support.
Fig. 18(Ignition Timing 100 BTDC)
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