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(i)
PERORMANCE ANALYSIS FOR HYDROGEN SUPPLEMENTED IN CI ENGINES
A MAJOR PROJECT
SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUIREMENT FOR THE AWARD OF DEGREE
OFBACHELOR OF TECHNOLOGY
IN
MECHAINCAL ENGINEERING
Submitted by:
HARMAN SINGH
(09109044)SURENDRA SINGH DHAKED
(09109084)
SURENDRA KUMAR MEENA
(09109083)
AVINASH KUMAR ROY
(09109025)
Under the guidance
Of
Dr. SARBJOT SINGH SANDHU
Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERING
Dr. B.R. AMBEDKAR NATIONAL INSTITUTE OF TECHNOLOGY
JALANDHAR
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CANDIDATES DECLARATION
We hereby declare that the work which is being presented in the Major Project report
PERORMANCE FOR HYDROGEN SUPPLEMENTED IN CI ENGINES submitted towards
the partial fulfillment of the requirements for the award of the degree of Bachelor of Technology in
mechanical Engineering, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar is anauthentic record of our work carried out from August 2012 to May 2013 under the supervision of Dr.
SARBJOT SINGH SANDHU, Assistant Professor, Department of Mechanical Engineering, Dr. B R
Ambedkar National Institute of Technology, Jalandhar.
The matter embodied in this Major Project report has not been submitted by us for any other degree or
diploma.
Place: NIT Jalandhar Harman SinghDate: 29/05/2013 Surendra Singh Dhaked
Surendra Kumar Meena
Avinash Kumar Roy
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CERTIFICATE
This is to certify that the above statement made by the candidates is correct to the best of my
knowledge.
(Dr. Subash Chander) (Dr.Sarbjot S.Sandhu)
Head of the Department Assistant Professor
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INDEX
1 ABSTRA CT. ...7
2 INTRODUCTION . ..8
2.1 LITERATURE REVIEW 9
2.1 .1 THERMODYNAMICS OF CI ENGINE....9
2.1.2 COMBUSTION IN CI ENGINES ....10
2.1.3 PROPERTIES OF HYDROGEN ...12
2.1.4 HYDROGEN SAFETY ISSUES . .15
2.1.5 FEATURES OF HYDROGEN FOR ENGINE APPLICATIONS 17
2.1.6 LIMITATIONS OF HYDROGEN ENGINE APPLICATIONS ..... ..18
2.1.7 FLASHBACK PREVENTION METHODS......19
2.1.8 FLASHBACK INTERRUPTION METHODS..18
2.1.9 S UMMARY OF PREVIOUS RESEARCH PAPERS...22.
3.1 EXPER IMENTAL SETUP2 6
4.1 EXPERI MENTAL PROCEDURE32
5.1 CALCULAT IONS AND RESULTS.34
6.1 REFE RENCES.......37
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List of Tables
2.1 Comparison of properties of hydrogen, methane and gasoline 15
5.1 Brake Thermal efficiency of engine using diesel 34
5.2 Calculation of required hydrogen at different loads 34
5.3 Results of Hydrogen Supplementation 35
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List of Figures
2.1 Indicator Diagram of a CI engine 9
2.2 P-v and T-s diagram of Dual Cycle 10
2.3 Fuel Jet of a CI engine 11
2.4 Cylinder pressure v/s cylinder pressure curve 12
2.5 Flame Arrestor with removable element from Enardo 20
2.6 Working of a flame arrestor 20
2.7 Detonation Arrestors 21
2.8 Example of Liquid seal flame arrestor 21
3.1 Schematic of Experimental Setup 26
3.2 Setup in Laboratory 27
3.3 Pressure regulator Used 28
3.4 Flow meter 29
3.5 CAD Model of Flame trap 30
3.6 Photo of Flame trap 31
5.1 Efficiency at different hydrogen supplementations 35
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1.1 ABSTRACT :-
Hydrogen is a versatile fuel with the unique potential of providing an ultimate freedom from energy (fuel)crisis and environmental degradation. The Present work describes the potential of hydrogen to be used for
stationary diesel engines or gensets which have agricultural applications. Hydrogen cannot be used directly in
a diesel engine due to its auto ignition temperature higher than that of diesel fuel. One alternative method is
to use hydrogen in enrichment in air mixture which could improve combustion efficiency of engine hence
increasing its Brake thermal efficiency. To investigate the combustion characteristics of this dual fuel engine,
a single cylinder diesel engine was modified to utilize hydrogen as fuel. Hydrogen was introduced to the intake
manifold before entering the combustion chamber. A flame trap was fabricated to inhibit any flashback if
generated .Engine was run at a constant speed of 1500 rpm and variable electrical loads. At each load step the
flow rate of hydrogen gas was varied. Fuel consumption, current and voltage output were measured
.Introducing Hydrogen improved the brake thermal efficiency.
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Chapter -2 Introduction
In the modern and fast moving world, petroleum based fuel have become important for a country s
development. Products derived from crude oil continued to be the major and critical source of energy for
fuelling vehicles all over the world. At the current and projected rate of consumption of crude, it is estimated
that these reserves will be badly depleted in due course and it may become impossible to meet the
requirements .Fossil fuels possess very useful properties not shared by non-conventional energy sources that
have made them popular during the last century. Diesel is mainly consumed in the transport, industries and
agricultural sectors. In the existing engines that have been designed to operate on petroleum-based fuels.
Developing countries, in particular, use small horsepower diesel engines for irrigation, pumping and other
agricultural activities. Diesel gensets have been found to be very effective as decentralized energy units for
various other applications. Unfortunately, fossil fuels are not renewable (Veziroglu TN. 1987) [1] in addition,
the pollutants emitted by fossil energy systems (e.g. CO, CO 2, CnHm, SOx, NOx, radioactivity, heavy metals,
ashes, etc.) are harmful and are causing global environmental problems like climate change. Global warming
and acid rains and more damaging than those that might be produced by a renewable based hydrogen energy
system (Winter CJ. 1987) [2]. A lot of research is being carried out throughout the world to evaluate the
performance, exhaust emission and combustion. characteristics of the existing engines using several
alternative fuels such as hydrogen, compressed natural gas (CNG), alcohols (methanol and ethanol), LPG,
biogas, producer gas, bio-diesels developed from vegetable oils, and a host of others. Practical implementation
of a particular fuel depends to a large extent on its .field of application, production potential, utilization, and
exhaust emission characteristics. There are other design-oriented problems such as fuel-induction technique
and on-board storage methods that need to be addressed from a practical point of view. A detailed study on
various alternative fuels is beyond the scope of this work.
In the context of the present work, the discussions will be restricted to hydrogen. Generally, the arguments for
and against hydrogen as an alternative fuel is based on some of its characteristics rather than on its Overall
characteristics. Clean burning, High flammability, High Calorific Value, High flame speed and rapid recycling
characteristics are on the positive side and the explosive characteristics are on the other side.
With this concept hydrogen is expected to be the future fuel for the internal combustion engines. Therefore
attempts have been made to utilize hydrogen in the compression ignition engine. But, hydrogen cannot be
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used as a sole fuel in compression ignition engine because of its high self-ignition temperature (858k),
therefore diesel is used as a main fuel. While hydrogen was inducted by mixing with air into the engine
In present work hydrogen is introduced in different equivalent energy ratios varying from 10 to 30 percent of
diesel calorific value through the inlet manifold and varying its flow according to required calorific value.
Due to high speed of flame flashback may rise which may be catastrophic if it reaches fuel tank.To prevent
the back fire of the flame after the combustion is over from the engine combustion liquid seal based flamearrestor is be installed in the system
2.1 LITERATURE REVIEW
2.1.1 Thermodynamics of Diesel Cycle [3]
Early CI engines injected fuel into the combustion chamber very late in the compression stroke, resulting in
the indicator diagram shown in Figure 2.1. Due to ignition delay and the finite time required to inject the fuel,
combustion lasted into the expansion stroke. This kept the pressure at peak levels well past TDC. This
combustion process is best approximated as a constant-pressure heat input in an air-standard cycle, resulting
in the diesel cycle shown in Figure 2.2. The rest of the cycle is similar to the air-standard otto cycle. The diesel
cycle is sometimes called a constant pressure cycle.
Figure 2.1 Indicator Diagram of a CI engine
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Figure 2.2 P-v and T-s diagram of Dual Cycle
2.1.2 Combustion Process
Combustion takes place in a CI engine in following steps:-
1. Atomization . Fuel drops break into very small droplets. The smaller the original drop size emitted by the
injector, the quicker and more efficient will be this atomization process.
2. Vaporization . The small droplets of liquid fuel evaporate to vapour. This occurs very quickly due to the
hot air temperatures created by the high compression of CI engines. High air temperature needed for this
vaporization process requires a minimum compression ratio in CI engines of about 12:1. About 90% of the
fuel injected into the cylinder has been vaporized within 0.001 second after injection. As the first fuel
evaporates, the immediate surroundings are cooled by evaporative cooling. This greatly affects subsequent
evaporation. Near the core of the fuel jet, the combination of high fuel concentration and evaporative cooling
will cause adiabatic saturation of fuel to occur. Evaporation will stop in this region, and only after additional
mixing and heating will this fuel be evaporated.3. Mixing . After vaporization, the fuel vapour must mix with air to form a mixture within the AF range
which is combustible. This mixing comes about because of the high fuel injection velocity added to the swirl
and turbulence in the cylinder air Figure 2.3 shows the non-homogeneous distribution of air-fuel ratio that
develops around the injected fuel jet. Combustion can occur within the equivalence ratio limits of cp = 1.8
(rich) and cp = 0.8 (lean).
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4. Self-Ignition. At about 8 bTDC , the air-fuel mixture starts to self-ignite. Actual combustion is preceded
by secondary reactions, including breakdown of large hydrocarbon molecules into smaller Species and some
oxidation. These reactions, caused by the high-temperature air, are exothermic and further raise the air
temperature in the immediate local vicinity. This finally leads to an actual sustained combustion process.
5. Combustion . Combustion starts from self-ignition simultaneously at many locations in the slightly rich
zone of the fuel jet, where the equivalence ratio is
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Generally, fuel economy is greater and the combustion reaction is more complete when a vehicle is run on a
lean mixture. Additionally, the final combustion temperature is generally lower, reducing the amount of
pollutants, such as nitrogen oxides, emitted in the exhaust. There is a limit to how lean the engine can be run,
as lean operation can significantly reduce the power output due to a reduction in the volumetric heating value
of the air/fuel mixture.
Low Ignition Energy
Hydrogen has very low ignition energy. The amount of energy needed to ignite hydrogen is about one order
of magnitude less than that required for gasoline. This enables hydrogen engines to ignite lean mixtures and
ensures prompt ignition.
Unfortunately, the low ignition energy means that hot gases and hot spots on the cylinder can serve as sources
of ignition, creating problems of premature ignition and flashback. Preventing this is one of the challengesassociated with running an engine on hydrogen. The wide flammability range of hydrogen means that almost
any mixture can be ignited by a hot spot.
Small Quenching Distance
Hydrogen has a small quenching distance, smaller than gasoline. Consequently, hydrogen flames travel closer
to the cylinder wall than other fuels before they extinguish. Thus, it is more difficult to quench a hydrogenflame than a gasoline flame. The smaller quenching distance can also increase the tendency for backfire since
the flame from a hydrogen-air mixture more readily passes a nearly closed intake valve, than a hydrocarbon-
air flame.
High Auto ignition Temperature
Hydrogen has a relatively high auto ignition temperature. This has important implications when a hydrogen-
air mixture is compressed. In fact, the auto ignition temperature is an important factor in determining what
compression ratio an engine can use, since the temperature rise during compression is related to the
compression ratio. The temperature rise is shown by the equation 2.1
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Table 2.1 Comparison of properties of hydrogen, methane and gasoline
2.1.4 Hydrogen Safety Issues [5]
Like any other fuel or energy carrier hydrogen poses risks if not properly handled or controlled. The risk of
hydrogen, therefore, must be considered relative to the common fuels such as gasoline, propane or natural gas.
Since hydrogen has the smallest molecule it has a greater tendency to escape through small openings than
other liquid or gaseous fuels. Based on properties of hydrogen such as density, viscosity and diffusion
coefficient in air, the propensity of hydrogen to leak through holes or joints of low pressure fuel lines may be
only 1.26 (laminar flow) to 2.8 (turbulent flow) times faster than a natural gas leak through the same hole (and
not 3.8 times faster as frequently assumed based solely on diffusion coefficients). Since natural gas has over
three times the energy density per unit volume the natural gas leak would result in more energy release than a
hydrogen leak.
For very large leaks from high pressure storage tanks, the leak rate is limited by sonic velocity. Due to higher
sonic velocity (1308 m/s) hydrogen would initially escape much faster than natural gas (sonic velocity of
natural gas is 449 m/s). Again, since natural gas has more than three times the energy density than hydrogen,
a natural gas leak will always contain more energy. If a leak should occur for whatever reason, hydrogen will
disperse much faster than any other fuel, thus reducing the hazard levels. Hydrogen is both more buoyant and
more diffusive than either gasoline, propane or natural gas. Hydrogen/air mixture can burn in relatively wide
volume ratios, between 4%and 75% of hydrogen in air. Other fuels have much lower flammability ranges,
natural gas 5.3-15%, propane 2.1-10%, and gasoline 1.2-6%. However, the range has a little practical value.
In many actual leak situations the key parameter that determines if a leak would ignite is the lower
flammability limit, an d hydrogens lower flammability limit is 4 times higher than that of gasoline, 1.9 times
higher than that of propane and slightly lower than that of natural gas.
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2.1.5 Features of Hydrogen for Engine Applications
In addition to the previous unique features associated almost exclusively with hydrogen, a number of others
can be cited in support of hydrogen applications in engines. To list some of the main of these features less
cyclic variations are encountered with hydrogen than with other fuels, even for very lean mixture operation.
This leads to a reduction in emissions, improved efficiency, and quieter and smoother operation. Hydrogen
can have a high effective octane number mainly because of its high burning rates and its slow resignation
reactivity.
Hydrogen has been shown to be an excellent additive in relatively small concentrations, to some common
fuels such as methane. Its gaseous state permits excellent cold starting and engine operation. Hydrogen
remains in gaseous state until it reaches its condensation point around 20 K. Hydrogen engines are more
appropriate for high-speed engine operation mainly due to the associated fast burning rates. Less spark
advance is usually needed, which contributes to better efficiencies and improved power output as the bulk of
the heat release by combustion can be completed just after the TDC region. Hydrogen engine operation can
be associated with less heat loss than with other fuels. Moderately high compression ratio operation is possible
with lean mixtures of hydrogen in air, which permits higher efficiencies and increased power output.
Hydrogen engines are very suitable for cogeneration applications since the energy transfer due to condensing
some water vapour can add up significantly to the thermal load output and the corresponding energyefficiency. Hydrogen unlike most other commercial fuels is a pure fuel of well-known properties and
characteristics, which permits continued and better optimization of engine performance. The reaction rates of
hydrogen are sensitive to the presence of a wide range of catalysts. This feature helps to improve its
combustion and the treatment of its exhaust emissions.
The thermodynamic and heat transfer characteristics of hydrogen tend to produce high compression
temperatures that contribute to improvements in engine efficiency and lean mixture operation. Hydrogen high
burning rates make the hydrogen fuelled engine performance less sensitive to changes to the shape of the
combustion chamber, level of turbulence and the intake charge swirling effect. Internal combustion engines
can burn hydrogen in a wider range of fuel-air mixtures than with gasoline.
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2.1.6 Limitations Associated with Hydrogen Engine Applications
Much of the information reported in the open literature about the performance of engines on hydrogen as a
fuel tends to highlight the positive features of hydrogen while de-emphasizing or even ignoring the many
limitations associated with such fields of application. There is a need to focus equally well on these and suggest
means for overcoming some of their negative aspects. Accordingly, the following is a listing of some features
associated with hydrogen as an engine fuel that may be considered as requiring some remedial action.
Hydrogen as a compressed gas at 200 atmospheres and atmospheric temperature merely occupy around 5%
of the energy of gasoline of the same volume. This is a major shortcoming particularly for transport
applications. Engines fuelled with hydrogen suffer from reduced power output, due mainly to the very low
heating value of hydrogen on volume basis and resorting to lean mixture operation. The mass of the intake air
is reduced for any engine size because of the relatively high stoichiometric hydrogen to air ratio.
There are serious potential operational problems associated with the uncontrolled resignation and backfiring
into the intake manifold of hydrogen engines. Hydrogen engines are prone to produce excessively high
cylinder pressure and to the onset of knock. The equivalent octane number of hydrogen is rather low in
comparison to common gasoline and methane. The high burning rates of hydrogen produce high pressures
and temperatures during combustion in engines when operating near stoichiometric mixtures. This may lead
to high exhaust emissions of oxides of nitrogen. There are serious limitations to the application of cold exhaustgas recirculation exhaust emissions control. Hydrogen engines may display some serious limitations to
effective turbo charging. There is always some potential for increased safety problems with hydrogen
operation. Hydrogen engine operation may be associated with increased noise and vibrations due mainly to
the high rates of pressure rise resulting from fast burning.
Great care is needed to avoid materials compatibility problems with hydrogen applications in engines. In
certain applications, such as in very cold climates, the exhaust emission of steam can be an undesirable feature
leading to poor visibility and increased icing problems.
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2.1.7 Flashback Prevention Methods [6]
Dilution
By adding inerts such as N 2 or CO 2, the mixture can be brought to a non-flammable state.
Cooling
For a flashback to progress into equipment, combustion heat must be transferred into the combustible mixture.
By passing a potentially flammable mixture through a water spray chamber or some sort of heat sink, a
flashback can be stopped. Mechanical inline flame arrestors and detonation arrestors are common heat sinks
2.1.8 Flashback Interruption Methods:-
Many methods to stop flashbacks have been devised. "Active" methods require maintenance of certain
parameters, such as liquid level or gas velocity. "Passive" methods require only routine inspection and
typically have no moving parts or instrument requirements.
Venturi type flame Arrestors (active)
Venturi flame arrestors simply create a restriction in the hydrocarbon/air mixture delivery pipe so that the gas
velocity is faster than the flame speed, preventing progression of a flashback upstream. Flashback in the
direction of flow can still happen. Even a partly closed valve can create a high velocity for flashback
prevention, but a Venturi shape creates much lower pressure drop. If gas flow stops, the venturi is no longer
effective, so methods to measure flow and add makeup gas (nitrogen, for instance) are often included
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Inline flame arrestors (passive)
Mechanical flame arrestors are filled with metal or ceramic, which absorbs heat from a flashback, quenching
it to a temperature below what is needed for ignition. This stops the flame. With a low enough
hydrocarbon/air mixture flow rate, if a flame travels to the face of the arrestor, it can become stable at that
point. Heating of the arrestor body and internals results. Once the arrestor temperatures increase enough,
ignition temperature can be reached on the upstream side of the arrestor and the flashback can proceed. For
this reason, a temperature switch is often installed on the flame side of each arrestor (adding an "active"
element). If an elevated temperature is detected, an alarm sounds and steps can be taken to stop flow
completely. An Enardo flame arrestor is shown below
Figure 2.5 Flame arrestor with removable element from Enardo
Figure 2.6 How a Flame arrestor works
Inline detonation arrestors (passive)
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Detonation arrestors are stronger, more effective versions of standard flame arrestors. They are certified
after extensive testing per U.S. Coast Guard standards, which specify piping arrangements certain to
accelerate a normal flash back to detonation speeds. The certified detonation arrestor must stop the flash
back without damage to the arrestor itself, so it can be used repeatedly if necessary.
FIGURE 2.7 Detonation arrestors from Protect seal
Liquid seal flame arrestors (active)
This type of flame arrestor works by bubbling the hydrocarbon/air mixture upwards through a liquid bath
(usually water), forming discrete bubbles. The gas exits above the liquid to the ignition source. A flash back
is stopped when flame is unable to move from bubble to bubble in order to reach the upstream pipe. Some
certification work has been done in Europe on this type arrestor, but so far there are no certified models on
the market. A common liquid seal flame arrestor design is shown below. Note the water level must be
maintained safely above the level of the safety at all times to insure bubbles.
FIGURE 2.8 Example of a Liquid seal flame arrestor
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2.1.9 SUMMARY OF PREVIOUS RESEARCH PAPERS ON SUBJECT
LM DAS [7] tells about various problems which arise in using H 2 as fuel include abnormal pressure rise and
preignition in combustion chamber at high loads and occasional backfire during idling. Due to its wide range
of flammability ultra-lean mixtures have been achieved to reduce NOx. One of the major issue of research is
induction technique for H 2 Fuel to ensure that there is no backfire. The fundamental properties that cause
backfire in a hydrogen engine system are its exceptionally low minimum ignition energy (0.02 mJ at 4
= 1) and the wide flammability limits (0.21 < (p < 7.34) of hydrogen-air mixture. Hydrogen is extremely
useful for automobile use in any weather conditions because it is gas till -253 degree Celsius Hydrogen is the
cleanest alternative fuel known. NO, is the only pollutant of concern in hydrogen engine and it has
been found to be greatly reduced in low ranges of equivalence ratio. Choice of the appropriate lubricant
for the hydrogen engine is also a very important factor. Sometimes particulate matter resulting from the
pyrolysis of lubricating oil vapors could be the cause of hot-spot-induced backfire. So in IIT Delhi Charge
Dilution technique has been used
In Experiment by N. Saravanan, G. Nagarajan Dual Fuel Mode was tested for CI engine using timed
manifold injection technique the hydrogen ow rate was varied in port injection system from 2 lpm to 9.5lpm. With optimized start of injection 5 degree CA BGTDC and 30 degree CA injection duration, hydrogen
ow rate was varied for optimization Experiments were carried out on a diesel engine with hydrogen in the
dual fuel mode t he optimum hydrogen ow rate was found to be 7.5 lpm based on the performance,
combustion and emissions behavior of the engine. The brake thermal efciency for hydrogen d iesel dual fuel
operation increased by 17% compared to diesel at optimized timings. Broader ammability limits of premixed
hydrogen ames than the hydrocarbon fuels resulted in leaner operation and hydrogen enhancing burning of
the diesel fuel, increase ef ciency. The NO x emission is found to be similar at 75% load and full load for both
hydrogen and diesel operation. However the concentration is lower at lower loads in hydrogen dual fuel
operation due to lean mixture operation. The smoke emission reduces by 44% in hydrogen diesel dual
operation compared to diesel operation. The CO and HC for hydrogen operation at optimized conditions are
same as that of diesel emissions. The engine operated smoothly with hydrogen except at full load that resulted
in knocking especially at high hydrogen ow rates. These experimental results can be used as a base for the
dual fuel applications and can be further extended to automotive applications. It can further be extended to
neat hydrogen application.
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Work by Toru Miyamoto , Hirokazu Hasegawa , Masato Mikami [8]. Experimentally investigated the
performance and emission characteristics of the diesel engine with hydrogen added to the intake air at late
diesel-fuel injection timings. The diesel-fuel injection timing and the hydrogen fraction in the intake mixture
were varied while the available heat produced by diesel-fuel and hydrogen per second of diesel fuel and
hydrogen was kept constant at a certain value. The main conclusions are as follows:
1. NO emission for hydrogen fraction of 8-10 vol. % was smaller than that without hydrogen at middle andhigh loads as the diesel-fuel injection timing was delayed until the expansion stroke
2. The maximum rate of in cylinder pressure rise decreased with increasing hydrogen fraction and attained
minimum around 10 vol. % hydrogen fraction.
3. In the case of diesel-fuel injection timings of 4-6 degree ATDC and 10 vol. % hydrogen fraction, the
maximum rate of in cylinder pressure rise was lower than 0.5 MPa/deg.
4. A combination of hydrogen addition and late diesel-fuel injection timing contributed to low temperature
combustion, in which NO decreased without the increase in unburned fuel.
5. Smoke emission increased with EGR rate. Addition of 3.9 vol. % hydrogen to the intake air, however,
decreased smoke emission by greater than 50%. The smoke reduction effect of hydrogen addition was greater
for higher EGR rate and later diesel-fuel injection timing.
6. In the case of diesel-fuel injection timing of -2 degree ATDC with 3.9 vol. %hydrogen addition, smoke
emission value was 0%, NO emission was low, the cyclic variation was low, and the maximum rate of in
cylinder pressure rise was acceptable under a nearly stoichiometric condition without sacrificing indicated
thermal efficiency.
In investigations by Anil Singh Bika, Luke Franklin, David B. Kittelson [9] varying proportions of
hydrogen and carbon monoxide (synthesis gas) have been investigated as a spark ignition (SI) engine fuel. A
single cylinder cooperative fuels research (CFR) engine was used to investigate the knock and combustion
characteristics of three blends of synthesis gas (H 2/CO ratio); 1) 100/0, 2) 75/25, and 3) 50/50, by volume.
These blends were tested at three compression ratios (6:1, 8:1, and 10:1), and three equivalence ratios (0.6,0.7, and 0.8). It was revealed that the knock limited compression ratio (KLCR) of a H 2/CO mixture increases
with increasing CO fraction, for a given spark timing. For a given equivalence ratio and spark timing, a
50%/50% H 2/CO mixture produced a KLCR of 8:1 compared to a 100% H 2 condition, which produced a
KLCR of 6:1. The burn duration and ignition lag also increased with increasing CO fraction. The results from
this work were important for those considering using synthesis gas as a fuel in SI engines. It revealed that
although CO is a slow burning fuel, higher CO fractions in synthesis gas can be beneficial, because of its
increased resistance to knock, which gives it the potential of producing higher indicated efficiencies through
the utilization of an engine with a higher compression ratio.
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In a work by D.B. Lata, Ashok Misra [10], experiments were performed on 4 cylinder turbocharged,
intercooled with 62.5 kW gen-set diesel engine by using hydrogen, liquefied petroleum gas (LPG) and mixture
of LPG and hydrogen as secondary fuels. The experiments were performed to measure ignition delay period
at different load conditions and various diesel substitutions. It is found that ignition delay equation based on
pressure, temperature and oxygen concentration for a dual fuel diesel engine run on diesel and biogas gives
variation up to 6.56% and 14.6% from the present experimental results, while ignition delay equation for a
pure diesel engine gives 7.55%and 33.3% variation at lower and higher gaseous fuel concentrations,
respectively. It is observed that the ignition delay of dual fuel engine depends not only on the type of gaseous
fuels and their concentrations but also on charge temperature, pressure and oxygen concentration
Paper by C. Liew, H. Li, J. Nuszkowski, S. Liu, T. Gatts, R. Atkinson, N. Clark [11]investigated the effect
of hydrogen (H 2) addition on the combustion process of a heavy-duty diesel engine. The addition of a small
amount of H 2 was shown to have a mild effect on the cylinder pressure and combustion process. When
operated at high load, the addition of a relatively large amount of H 2 substantially increased the peak cylinder
pressure and the peak heat release rate. Compared to the two-stage combustion process of diesel engines, a
featured three-stage combustion process of the H 2-diesel dual fuel engine was observed. The extremely high
peak heat release rate represented a combination of diesel diffusion combustion and the premixed combustion
of H 2 consumed by multiple turbulent flames, which substantially enhanced the combustion process of H 2-
diesel dual fuel engine. However, the addition of a relatively large amount of H 2 at low load did not change
the two-stage heat release process pattern. The premixed combustion was dramatically inhibited while the
diffusion combustion was slightly enhanced and elongated. The substantially reduced peak cylinder pressure
at low load was due to the deteriorated premixed combustion.
In a paper by Andre Marcelino de Morais, Marco Aurelio Mendes Justino, Osmano Souza Valente,
Sergio de Morais Hanriot, Jose Ricardo Sodre [12]investigates the performance and carbon dioxide (CO 2)
emissions from a stationary diesel engine fuelled with diesel oil (B5) and hydrogen (H 2). The performance
parameters investigated were specific fuel consumption, effective engine efficiency and volumetric efficiency.
The engine was operated varying the nominal load from 0 kW to 40 kW, with diesel oil being directly injected
in the combustion chamber. Hydrogen was injected in the intake manifold, substituting diesel oil in
concentrations of 5%, 10%, 15% and 20% on energy basis, keeping the original settings of diesel oil injection.
The results show that partial substitution of diesel oil by hydrogen at the test conditions does not affect
significantly specific fuel consumption and effective engine efficiency, and decreases the volumetric
efficiency by up to 6%. On the other hand the use of hydrogen reduced CO 2 emissions by up to 12%, indicating
that it can be applied to engines to reduce global warming effects.
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3.1 Experimental Setup
Our system consisted of following components
Hydrogen Cylinder at 200 bar
Pressure regulator
Flow meter
Flame arrestor
Pressure Gauge
Inlet manifold
Single Cylinder engine
Exhaust
Hydraulic hoses
Figure
3.1 Experimental setup
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Figure 3.2 Setup in Laboratory
Hydrogen Cylinder : - Metal tank is used to contain hydrogen.it is cylindrical and manufactured from steel
and contains H 2 up to 200 bar
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Pressure regulator : - A pressure regulator is a self-contained mechanical control device that usually does not
rely on any external power sources. This device employs a sensor, valve, and controller unit. Although the
two are similar, it is important to make the distinction between a regulator and a control valve. Regulators
tend to be less expensive and relatively easier to install and maintain. However, applications requiring larger
valve sizes may be better served by control valve systems.
When working with compressed gas in cylinders or other containers, pressure regulators are vital for
maintaining proper gas discharge. These regulators are employed for controlling both liquefied and non-
liquefied gas forms. While there are numerous types of different gas regulators, most devices are selected
based on their range of delivery pressures, their level of accuracy, the quality of their design and construction
materials, and the flow rate involved in the project.
Fig 3.3 Pressure regulator Used
Flow meters
Flow meters on modern anesthetic machines consist of a tapered glass tube containing a ball which floats on
the stream of moving gas.
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Figure no. 3.4 Flow meter
As the gas flow rate increases, the float is carried further up the tube, so indicating the flow rate.
Flow meters are specifically constructed for each gas, since the flow rate depends on both the viscosity
and density of the gas.
Only the correct tube and bobbin or ball can be used to repair broken flow meters.
Since the ball floats in the gas stream, flow meters will only function correctly if the tube is vertical.
Flow meters will not function correctly if the tube is cracked.
Ball-float flow meter,
reading 2 l/min
Inaccuracy in flow meters
May be due to:
The tube not being vertical.
Back-pressure from, for example, a ventilator.
Static electricity causing the float to stick to the tube. Dirt causing the float to stick to the tube.
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Flame Trap fabrication: -
For the purpose of flashback arrestor, a liquid seal flame arrester flame trap was fabricated from sheet metal
(Hot rolled steel) for 10 bar max. pressure Liquid seal of water was used and hydraulic hoses of R15 grade
was inserted at inlet. Design of flame trap was conceptualized using eqn 4.1(pressure vessel) and dimensions
were assumed to be 1 feet(300 mm) height and 1.5 feet(450 mm) diameter. To sustain 10 bar pressure required
thickness of 1.5 mm if material was cold rolled steel/black sheet metal (strength =180Mpa)
Sheet metal was developed as a cylinder and it was completed through gas welding .Then a quarter spherical
flare stack was attached to cylinder using rubber sealing which was bonded together with steel using rubber
adhesive
At Inlet and outlet nuts were brazed and at outlet side a globe valve, pressure gauge and flow meter was
installed
FIGURE NO 3.5 CAD MODEL OF FLAME TRAP
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Figure no 3.6 Photo of Flame trap
,
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4.2.2 Calculation of hydrogen for equivalent calorific value
As experiment is based on adding hydrogen at equivalent CV of diesel at 10, 15,20,25,30 percent of diesel
using formula
( ) = 6 10 9
.082 3600 (4.2)
Where
c = required percentage
P = pressure
4.2.3 Calculation of brake thermal efficiency with Hydrogen
While operating in hydrogen supplementation mode efficiency can be calculated as follows
= ( + )
(4.3)
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Discussions :-
It is found that system gives optimum efficiency around 10% at lower loads and it is expected that it will be
around 15-20% at higher loads
Therefore, It is required to improve the system by refabricated the flame trap which can be done by using
sheet metal of greater thickness and using welding to assemble flame trap rather than adhesive bonding
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