KB7005 Advanced Internal Combustion Engines and Alternative Fuels Laboratory work assignment

This document is a laboratory work assignment for the course KB7005 Advanced Internal Combustion Engines and Alternative Fuels. It provides an introduction to internal combustion engines, the aim of the experiment, experiment equipment, procedure, results and data, discussion, and conclusion.

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KB7005 Advanced Internal Combustion
Engines and Alternative Fuels
Laboratory work assignment
IC Engine Performance and pollutant
emission
Student Name
Student Registration Number
Date of submission

INTRODUCTION
The internal combustion engines are heat engines where the heat source is a combustible mixture
that also serves as the working fluid. It has a gas turbine and is propelled using gasoline or diesel.
The heating process at the exhaust system may follow the Otto Cycle but the main power is used
to overcome the air resistance. There is a production of pollutants with a non-equilibrium effect
which may degrade the environment.
AIM OF THE EXPERIMENT
(i) To measure the engine performance and formation of pollutants in the combustion
process.
Experiment Equipment
The emission equipment used in the experiment is the Horiba Mexa FT-one system
Experiment Procedure
(i) The Horiba exhaust gas sampling system was prepared
(ii) The intake temperature and pressure measurements were taken
(iii) The exhaust system was set to measuring mode, the engine was switched to motoring
mode at 2000 rpm and was able to warm up to attain a steady state operation.
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(iv) The pressure transducer and charge amplifier system were setup and the pressure
trace was obtained from the oscilloscope. The peak motoring pressure and the
composition of the gas going through the exhaust at that point was measured.
(v) The injection time and duration was set and adjusted accordingly in the experiment.
EXPERIMENT RESULTS AND DATA
The crank angle versus the in-cylinder pressure is given as,
The data obtained for the pressure curves in 9 different engine operating conditions were
recorded on excel spreadsheets. The relationship between the crank angle and the in-cylinder
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pressure was obtained as illustrated in the figure above. Further, the Horiba exhaust emission
control machine record data was obtained for different motoring conditions.
DISCUSSION
From the motoring pressure curve, calculate the polytropic index for the compression process
and, using it, the peak temperature at the end of the compression
W =cdv /v n
w= P1 v1−P2 v2
n−1
du=dq – dw
u 2 – u 1=q− P1 v1−P2 v2
n−1
u2 – u1=C v (T 2 – T1 )=q – w
q=R T 2 – T 1
−1 + P1 v1 −P2 v2
n−1
¿ R ( T 1 – T 2 ) { 1
n−1 – 1
−1 }
¿ P1 v1 −P2 v2
n−1 {−n
−1 }
¿ w . {−n
−1 }
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Considering that the oxygen gas produced at the exhaust is
¿ 1.66
P 2=P 1 ( v 1
v 2 )
1.25
=100∗( 1700
3500 ) =48.6 bars
T 2=T 1 P2 v2
P1 v1
T 2=(300 K )(48.6)(100)
(100∗35) =416.6 K
Neglecting product dissociation, derive the relationship between the oxygen content in the
exhaust gas and the mixture overall equivalence ratio
fuel+O2 → Products+ Heat
stoichiometri cratio= actualair
stoichometri cair
The volume of the stoichiometric air is
¿ 2
21∗100=9.524 m3
The volume of the actual air is,
¿ 9.524 ( 1+0.18 ) m3=11.238 m3
The volume of oxygen is given as,
¿ 2 m3∗0.18=0.36 m3
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The percentage of carbon dioxide,
¿ 1
10.238∗100=9.767
Estimate the combustion duration for different operating conditions using the measured in-
cylinder pressure curves.
The combustion duration is estimated as,
¿ 15 msec+ 25 msec+1.25 msec
¿ 41.25 msec
Assuming that
a) The combustion is fast, and b) happens at TDC, c) there are no trapped residuals, and d) the
combustion products are at a thermochemical equilibrium, determine the temperature and
pressure and burnt gas composition
C H 4+2O2=C O2+2 H2 O
C H 4+ 2O2 +7.5 N2=C O2 +2 H2 O+7.5 N2
The thermo-equilibrium composition of the methane to air mixtures is obtained as illustrated in
the following table,
Species Successive
substitution algorithm
NASA SP-273 AEDC-TR-71-256
Oxygen 0.02010 0.02010 0.02010
Water 0.11320 0.11320 0.11320
Nitrogen 0.72841 0.72841 0.72841
Nitrogen oxide 0.00001 0.00001 0.00001
Carbon (IV) oxide 0.13827 0.13827 0.13827
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The equilibrium constant curve fit is obtained using the recommended Arrhenius type curve
obtained using the constant given as,
Kc= A T B e
−C
T
ln ( K c ) =ln ( A ) +B∗ln ( T ) + C
T
When evaluated for more species such as the oxygen, hydrogen, and hydroxide, the following
chart is illustrated,
For other species such as the water, nitrogen, and nitrogen oxide, the chemical equilibrium
constants are varied against temperature to obtain,
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For the carbon components and the compounds,
The standard error was estimated as,
S= √ ∑
i=1
N
yi
fit − yi
data2
N−F
For the total number of data points and functions in the curve fit, N and F respectively
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There are 9.5 moles of air used in the combustion process. The observed trends in amounts of
nitrogen oxides in the exhaust gases
Volum enitrogen=11.238 m3∗0.79=8.878 m3
The calculated values against the measured values demonstrate a slight discrepancy which can be
attributed to environmental factors and incomplete combustion.
Mixture Pressure, atm Temperature, K Theoretical air,
percent
Methane/air 1.0 1000.0 110.0
Propane/air 50.0 2500.0 100.0
CONCLUSION
In a nutshell, with proper amounts of oxygen, the system is able to remove the waste from the
internal combustion engine. There is a pollution factor to be taken into consideration. When the
oxygen supplied in the ICE is not sufficient, the system tends to produce byproducts which are
harmful to the environment.
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REFERENCES
Eugene L. Keating, (2007). Applied Combustion, Second Edition, , CRC Press (Taylor and
Francis Group), NY.
Sakar, S,. (2009) Fuels and Combustion, , 3rd Edition, University Press, India.
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