International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
Research Article
EXPERIMENTAL INVESTIGATION ON VARYING
ENGINE TORQUE OF SI ENGINE WORKING UNDER
GASOLINE BLENDED WITH OXYGENATED ORGANIC
COMPOUNDS
D.Balaji¹*, Dr.P.Govindarajan², J.Venkatesan³
Address for Correspondence
¹Research scholar, Anna University Coimbatore, Department of Mechanical Engineering, Panimalar
institute of Technology, Chennai-602103
²Principal, Sona College of technology, Salem-5
³Department of Mechanical Engineering, Sri Venkateswara College Engineering Chennai-602105
E mail [email protected]
ABSTRACT
This paper investigates the effect of using unleaded gasoline and additives blends on spark ignition engine (SI engine)
performance, combustion and exhaust emission. A four stroke, single cylinder SI engine was used for conducting this
study. Performance tests were conducted for fuel consumption, volumetric efficiency, brake thermal efficiency, brake
power, engine torque and brake specific fuel consumption, while exhaust emissions were analysed for carbon monoxide
(CO), Hydrocarbon (HC), and Oxides of nitrogen (NOx) using unleaded gasoline and additives blends with different
percentages of fuel at varying engine torque condition and constant engine speed. The result showed that blending
unleaded gasoline with additives increases the brake power, volumetric and brake thermal efficiencies and fuel
consumption. The CO and HC emissions concentrations in the engine exhaust decreases while the NOx concentration
increases.
KEYWORDS: Fuel additive; Gasoline-Additives blend; Exhaust emissions
1. INTRODUCTION
the atmosphere and become hazardous to health
It is the dream of engineers and scientists to
[3]. The emissions exhausted into the surroundings
develop engines and fuels such that very few
pollute the atmosphere and cause global warming,
quantity of harmful emissions are generated, and
acid rain, smog, odours, respiratory and other
these could be let into the surroundings without a
health hazards. The urgent need for alternative fuel
major impact on the environment. Air pollution is
is essential to replace the supplement conventional
predominately emitted through the exhaust of
fuels. A pollutant is a component which changes
motor vehicles and the combustion of fossil fuels.
the balance of environment and nature under
Government around the world has set forth many
normal
regulatory laws to control the emissions. One of
considered as pollutant as nature recycles it and
the
modern
produces oxygen but in a confined area if CO2
technological society is the drastic increase in
exceeds 5000 ppm then it becomes a potential
environmental pollution by internal combustion
health hazard [7],[9]. The root cause for these
engines (IC engines). All transport vehicles with
emissions
SI and CI (compression ignition) engines are
dissociation of nitrogen and impurities in the fuel
equally responsible for the emitting different kinds
and air. The transportation which uses IC engines
of pollutants. Some of these are primary kinds
is the major sector for the economic growth. The
having direct hazardous effect such as carbon
major exhaust emissions HC, CO, NOx, SO2, solid
monoxide, hydrocarbons, nitrogen oxides etc,
particles etc are and performance is increased by
while others are secondary pollutants such as
adding the suitable additives to the fuel reduced
ozone, etc., which undergo a series of reactions in
with the present technology. Additives are integral
serious
problems
facing
the
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
condition.
is
Carbon
dioxide
non-stoichiometric
is
not
combustion,
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
part of today’s fuel. Together with carefully
Siddique [4] Hamdan, Jurban [5] and El-Kassaby
formulated base fuel composition they contribute
[6] have studied the effect of using ethanol-
to efficiency and long life. They are chemicals,
gasoline blends. They used maximum of 15 % of
which are added in small quantities either to
ethanol in ATd 34 engine. Palmer F H [2] has
enhance fuel performance, or to correct a
conducted a test on gasoline engine containing
deficiency as desired by the current legislation.
oxygenates. The effect of oxygenate in gasoline on
They can have surprisingly large effects even
exhaust emission and performance in a single
when added in little amount [10]. Additives are
cylinder, four stroke SI engine was studied by
blended into fuel by refineries or end users.
Taljaard et al [8]. Based on the economic and
However
was
environmental considerations, an attempt has been
subsequently discontinued mainly because of
made in this work to study the effects of ethanol
concern about the toxicity of the barium
contents in the ethanol-gasoline blended fuel on
compounds in the exhaust emission. But the
the engine performance and pollutant emission of
interest is revised recently to verify the possible
a commercial SI engine. In the present work, to
use of additives to reduce emission level. Alcohol
reduce the emissions and to improve the
has been used as a fuel for Auto-engines since 19th
performance of petrol engine, the modification
century; it is not widely used because of its high
technique is used. Two fuel additives were mixed
price. Alcohol is one of the fuel additive
for this purpose. Various proportions of these fuel
(Methanol, Ethanol) has some advantage over
additives were mixed with the gasoline. The
gasoline such as better antiknock characteristics
engine performance analysis and emission levels
and the reduction of CO and HC emissions.
were measured, running the engine at varying load
Houghton-Alico D [1] has made a study on
and constant speed. Encouraging results were
alcohol production and potential. Several additives
obtained and the work carried out is presented.
(oxygenated
as
The objective of the present work is to investigate
methanol, ethanol, tertiary butyl alcohol and
the effect of varying engine torque on the engine
methyl tertiary butyl ether are used as fuel
performance and exhaust emission working with
additives. Although having these advantages, due
different ethanol fuel blends.
to limitations in technology, economic and
2. Experimental set up and method
regional considerations alcohol fuel still cannot be
The engine is a 100 cc 4 stroke, single cylinder
used extensively. Since ethanol can be fermented
SI
and distilled from biomasses, it can be considered
dynamometer. Table 1 lists some of the
as renewable energy under the environmental
important specification of the engine under test.
consideration, using ethanol blended with gasoline
The schematic layout of the experimental set up
is better than methanol because of its renewability
is shown in fig 1. The engine was coupled to a
and less toxicity. Many researchers have worked
eddy current dynamometer which is quipped
on
performance
with an instrument cabinet fitted with a torque
enhancement of SI engines. Winnington and
gauge, electric tachometer and switches for the
the
use
of
metallic
organic
emission
additives
compounds)
control
and
such
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
engine
loaded
by
an
eddy
current
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
load remote control. Fuel consumption was
The air fuel ratio was adjusted to yield
measured by using a calibrated burette and a
maximum power on unleaded gasoline. Engine
stopwatch with an accuracy of 0.2s. The
test were performed at constant engine speed at
concentration of exhaust emission (CO, HC,
3/4th throttle opening position by varying engine
NOx) and air fuel ratio were measured using a
torque. The speed can be maintained constant by
“Sun glass Analyser” MGA 1200. The analyser
speed sensor. Before running the engine to a
has a non-dispersive infrared molecule for CO,
new fuel blend, it was allowed to run for
HC and NOx. The engine was started and
sufficient time to consume the remaining fuel
allowed to warm up for a period of 20-30 min.
from
1.
2.
3.
4.
5.
6.
7.
8.
9.
Engine
Eddy current dynamometer
Electric pressure pickup
Personal computer
Printer
Load sensor
RPM Counter
Dynamometer control Panel
Exhaust gas temperature
10.
11.
12.
13.
14.
15.
16.
17.
18.
the
previous
experiment.
Moisture separator
Exhaust gas analyzer
Carburetor
Air filter
Air box
Orifice meter
Exhaust pipe
Shaft
Fuel measuring unit
Fig 1 Experimental setup
Table 1 Engine specifications
Engine make and model
Bajaj engine
Engine type
Bore
Stroke
Cubic capacity
Four stroke, Single cylinder air cooled engine
70 mm
90 mm
100 cc
Compression ratio
7.4:1
Rated power
Rated speed
5.2 kW
6500 rpm
Fuel
Petrol
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
For each experiment, three runs were performed to
that of the unleaded gasoline fuel. Therefore the
obtain an average value of the experimental data.
amount of fuel introduced in to the engine cylinder
The variables that were continuously measured
for a given desired fuel energy input has to be
include engine speed (constant), torque, time
greater with the ethanol fuel.
required to consume 100 cc of fuel blend, CO, HC,
3.2 Volumetric efficiency
NOx emission and exhaust gas temperature. The
The effect of ethanol and unleaded gasoline fuel
parameters such as fuel consumption rate,
blends on the volumetric efficiency is shown in
volumetric efficiency, brake power, brake thermal
Fig 3. Fig 3 clearly indicates an increase of
efficiency were estimated by standard equations.
volumetric efficiency with the engine torque upto
Table 1 shows the engine specification.
0.9 Nm. This is due to decrease of the charge
3. Result and Discussion
temperature at the end of the induction process and
The effect of ethanol addition to unleaded gasoline
the increase of the amount of air introduced in the
on SI engine performance and exhaust emissions
engine
th
cylinder.
This
decrease
in
charge
at 3/4 throttle opening at various engine torque
temperature is attributed by an amount as a result
were investigated.
of the heat transfer from hot engine parts and the
3.1Fuel consumption
residual gases in the charge. At the same time, the
The effect of ethanol-unleaded gasoline blends on
charge temperature drops by an amount due to
the fuel consumption is shown in Fig 2. From Fig
vaporization of the fuel blend in the inlet manifold
2, the fuel consumption increases on the engine
and engine cylinder. Further increase in engine
torque increases at constant engine speed. This
torque
behaviour is attributed to the LHV per unit mass
efficiency, where the amount of air decreases as a
of the ethanol fuel, which is distinctly lower than
result of choking in the induction system
results
in
Fig 2 Engine torque – Fuel consumption chart
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
a
decreasing
volumetric
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
.
Fig 3 Engine torque – Volumetric efficiency chart
3.3 Brake thermal efficiency
3.4 Specific fuel consumption
Fig 4 presents the effect of ethanol-unleaded
The effect of using ethanol-unleaded gasoline
gasoline blends on brake thermal efficiency. As
blends on brake specific fuel consumption
shown in the figure break thermal efficiency
(BSFC) is shown in Fig 5. As shown in the
increases as the engine torque increases. The
figure SFC decreases as the engine torque
maximum brake thermal efficiency is recorded
increases. This is normal consequence of the
with 10% ethanol in the fuel blend at constant
behaviour
engine speed.
efficiency.
of
the
engine
Fig 4 Engine torque – Brake thermal efficiency chart
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
brake
thermal
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
Fig 5 Engine torque – Specific fuel consumption chart
3.5 Exhaust emissions
emission increases as compared with gasoline
The effect of the Ethanol percentage in the fuel
fuel for various blends. Fig 8 shows that HC
blend on the CO, HC, and NOx is shown in Fig
emission decreases as compared with petrol fuel
6 - 8. Fig 6 shows that the CO emission
for various blends. It can be seen that as the
decreases as compared with petrol fuel for
ethanol percentage increases to 20%, the CO and
various blends. Due to better combustion these
HC concentration decrease for all engine torque
emissions are decreased. Fig 7 shows that NOx
values.
Fig 6 Engine torque – CO emission chart
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
International Journal of Advanced Engineering Technology
E-ISSN 0976-3945
Fig 7 Engine torque – NOx emission chart
Fig 7 Engine torque – HC emission chart
The fuel specification (density, RVP (reid vapour pressure), heating value, etc) is shown in Appendix A.
Appendix A Fuel Specification
Property
Density (kg/l)
RON (Octane number)
RVP (kPa)
Heating value (cal/g)
Carbon (Wt %)
Hydrogen (Wt %)
Residue
Colour
E0
0.7575
95.4
53.7
10176
86.60
13.3
1.7
Yellow
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
E10
0.7608
98.1
59.6
9511
86.70
13.2
1.5
Yellow
E20
0.7645
100.7
58.3
9316
87.60
12.3
1.5
Yellow
E30
0.7682
102.4
56.8
8680
86
13.9
1.5
Yellow
International Journal of Advanced Engineering Technology
4. CONCLUSION
1. Using ethanol as a fuel additive to
unleaded
gasoline
causes
an
improvement in engine performance and
exhaust emissions.
2. Ethanol addition results in an increase in
brake power, brake thermal efficiency,
volumetric
efficiency,
and
fuel
consumption by about 8.2%, 9%, 7%
and
5.7%
mean
average
values
respectively. In addition, the brake
specific fuel consumption decreases by
about 2.4% mean average value.
3. Using ethanol-unleaded gasoline blend
leads to a significant reduction in
exhaust emissions by about 46.5% and
24.3% of the mean average values of
CO and HC emission respectively for all
engine torque, on the other hand NOx
emissions increases for all engine torque
values.
4. The addition of 30% ethanol to the
unleaded gasoline is achieved on our
experiments
without
any
problems
during engine operation.
ACKNOWLEDGEMENT
The author would like to thank the technical
staff of the ICE laboratory at the Mechanical
Engineering Department of Sona College of
Technology.
REFERENCES
[1] Houghton-Alico D (1982), Alcohol fuels
production and potential, Colorado.
[2] Palmer F H (1986), Vehicle performance of
gasoline containing oxygenates, paper C319/86,
International conference on petroleum based fuels
and automotive applications, London, I. Mech. E.
Conference, pp. 36-46.
[3] Goddger E M (1975), Hydrocarbon fuel, London,
Macmillan.
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/65-73
E-ISSN 0976-3945
[4] Winnington T L and Siddiqui KM (1983), Engine
performance on gasohol-the Kenyan experience,
Automotive engineering.
[5] Hamdan M A, Jubran BA (1986), .The effect of
ethanol performance of diesel and petrol engines,
Dirasat, XIII(10), pp. 229-244.
[6] EL-Kassaby M M (1993), Effect of using
differential ethanol-gasoline blends at different
compression ratio on SI engine, Alexandria
Engineering, pp.135-145.
[7] Bata R V, Roan V P (1989), Effects of ethanol
and methanol in alcohol-gasoline blends on exhaust
emission, J. Engineering, Gas Turbine Power, ASME,
pp.432-438.
[8] Taljaard H C, Jaardaan CFP, Both JJ (1991), The
effect of oxygen content in different oxygenates
gasoline blends on performarence and emission in a
single cylinder spark ignition engine, SAE 91037.
[9] Unzelman J B (1991), US Clean Air Act expand
role for oxygenates; oxygenates for the future, Oil
and Gas Journal, pp.44-48.
[10] Gulder L O (1979), Technical aspect of ethanol
and ethanol gasoline blends as automotive fuel, The
scientific and Technical Research Council of Turkey,
Project No. 526.