perormance and emission analysis for hydrogen supplementation in ci engines

8/13/2019 Perormance and Emission Analysis for Hydrogen Supplementation in Ci Engines

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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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perormance and emission analysis for hydrogen supplementation in ci engines

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