106553270 Hydrogen Fuel Rotary Engine

A

Seminar Report

On

ByRavindra Bhaskar Mali

B.E. (MECH) [email protected]

Atul Suresh Sonawane T.E. (MECH) [email protected]

Guided by:Prof. M. V. Nagarhalli

DEPARTMENT OF MECHANICAL ENGINEERINGS.R.E.S’S COLLEGE OF ENGINEERING, KOPARGAON - 423603

UNIVERSITY OF PUNE

mailto:[email protected]

Hydrogen Fueled Rotary Engine_______________________________________________________________________

ABSTRACT

We are aware that in early future the world will suffer from the shortage of

conventional fuels. Pollution from these conventional fuels is causing the global warming, ozone

depletion this makes it essential to search the renewable, pollution free alternative fuel. Hydrogen

seems to be most promising alternative fuel.

Hydrogen when burns produce clean energy. Hydrogen can be produce easily.

Hydrogen is lightest fuel and richest in energy per unit mass (120 700 kJ/kg). Petrol vapor creeps

along the ground while Hydrogen goes up in the air so it is relatively safe. Hydrogen can be stored

as compressed gas, liquid or by chemical bonding (i.e. Metal Hydride). Some alloys stores

Hydrogen at a higher density than pure Hydrogen even higher than the liquid Hydrogen.

Hydrogen, like petrol, diesel and natural gas, burns well in internal combustion

engines. However, in Reciprocating engine during the suction stroke if the Hydrogen is expose to

the red-hot particle or spark plug and pre-ignition takes place then it can burst entire fuel tank.

Solution to these problems is to use the Hydrogen in the Wankel rotary engine,

which has advantages like high power to weight ratio, extended power stroke, and lesser moving

parts. Rotor directly opens and closes ports, so correct timing of intake and exhaust is maintain even

at high speed with flat torque curve. Vibration is very low because perfect balancing is possible.

Cooler combustion means fewer oxides of nitrogen. Separation of combustion region from intake

region is good for Hydrogen fuel.

Mazda began a two years trial period for its experimental low-pollution Hydrogen

rotary engine vehicle in 1995. The Cappella Cargo van model vehicle will burn a Hydrogen fuel

and will not emit carbon dioxide. Mazda lent the vehicle to the Hirohata Steel Mill for use as their

company van and drove it for at least 20,000 kilometers on public roads. Hydrogen was stored as

metal hydride.

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INDEX

Sr. No: Chapter Page No.

1. Introduction 3

2. Hydrogen Energy- A Brief Introduction 4

2.1 From carbon to hydrogen 4

2.2 Generating Hydrogen 5

2.3 Storing the Hydrogen 5

2.4 Hydrogen in internal combustion engines 6

3. Wankel engine 7

3.1 Glossary of terms 7

3.2 Working of Wankel engine 8

3.3 Advantages 9

3.4 Disadvantages 9

4. Case Study: 10

4.1 Mazda HR-X car 10

4.2 Test results 10

5. Conclusion 12

Bibliography 13

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Chapter: 1 Introduction:

All of us are aware that in future the world will suffer from the shortage of

conventional fuels like coal, petroleum and its products. Over the last five years the world used 27

billion barrels of oil each year, while annual discoveries amounted only 3 billion barrels. Following

chart shows, the oil discovered worldwide every five years. (Refer figure 1.1)

Figure No: 1.1

Trend in volume of oil discovered worldwide

as per international energy agency’s assessment

Therefore, there is need of the alternative fuels, which will overcome the above

problems. There are many alternative fuels like methanol, ethanol, bio-diesel, hydrogen etc.

Hydrogen seems to be most promising alternative fuel. It is an energy dense, pollution free

renewable fuel.

Hydrogen and electricity are the only energy carriers available that can be completely

pollution free. Electricity has already proved its value but is not a useful form of energy in remote

areas or in transport, primarily due to difficulties of storage. While Hydrogen is also difficult to store

and transport, over long distances it becomes more efficient to use Hydrogen than electricity.

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50

100

150

200

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1940 1950 1960 1970 1980 1990 2000 2010

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Volume of oildiscovered worldwideevery 5 years (MillionBarel)


Chapter: 2 Hydrogen Energy - A Brief Introduction

From carbon to Hydrogen

Until the industrial revolution, the main source of energy for most people was wood -

a hydrocarbon fuel. Improved technology led to widespread use of coal (more Hydrogen, less

carbon), and then to oil and natural gas.

Hydrogen burns to produce water. Hydrogen is relatively safe because it vents

upwards. Gasoline (petrol) is more dangerous because its vapors creep along the ground. Hydrogen

has the highest energy content per unit weight of any known fuel-52,000 Btu/lb (1,20,700 kJ/kg).

When Hydrogen is burned with oxygen, the only byproducts are heat and water. Hydrogen is a

colorless, odorless, tasteless, flammable and nontoxic gas at atmospheric temperatures and

pressures. It is the lightest gas known, being only some seven one hundredths as heavy as air.

Hydrogen is present in the atmosphere, occurring in concentrations of only about 0.01 per cent by

volume at lower altitudes.

Properties of Hydrogen:

Auto ignition temperature : 520 0C (968 0F)Density : 0.08342 kg/m3

Diffusivity : 1.697 m2/hrFlame temperature : 2318 0C (4202.4 0F)Specific gravity : 0.6960 (air = 1)Specific volume : 11.99 m3/kg (191.98 scf/lb)

Properties Gasoline Diesel Fuel

Methanol

Ethanol Natural Gas (CNG)

Propane Hydrogen

Chemical Formula

C4 to C12 C3 to C25 CH3OH C2H5OH C3H8 CH4 H2

Molecular Weight

100–105 200 32.04 46.07 44.1 16.04 2.02

Boiling temperature °F

80–437 370–650

149 172 -44 -259 -423

Octane no 90–100 ------- 107 108 112 ------ 130+

Freezing point 0C

-40 98 -115 -305.8 -296 -435

Flash point, closed cup, °F

-45 165 52 55 -100 to -150 -300 --

Auto-ignition 257 315-460 422 422 454–510 540 565-580

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temperature, °C

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2.2 Generating the Hydrogen:

2.2.1 Hydrogen from water: - The most common way of splitting water is by

electrolysis, though it can also be done using a thermochemical reaction or simply by

heating.

2.2.2 Hydrogen from hydrocarbons: - The cheapest way of making Hydrogen at

present is by reforming it from natural gas. Most of the Hydrogen in use today is made by

this method. In order to split the Hydrogen from the carbon in the natural gas (mainly

Methane, CH4) a process called “steam reformation” is used.

Storing the Hydrogen : - Since Hydrogen is one of the lightest elements and has very small

molecules, it can escape from tanks and pipes more easily than conventional fuels. However,

if it is to be used as a fuel for transport or power generation then there must be ways of

storing it cost-effectively. Storing Hydrogen can be done in three main ways, compressed

form, in Liquid form and by chemical bonding (i.e. Metal Hydride).

A gram of Hydrogen gas occupies about 11 liters (2.9 gallons) of space at

atmospheric pressure, so for convenience the gas must be intensely pressurized to several hundred

atmospheres and stored in a pressure vessel. In liquid form, Hydrogen can only be stored under

cryogenic temperatures. These options are not practical for everyday use. The solution to these

difficulties is storage of Hydrogen in hydride form. This method uses an alloy that can absorb and

hold large amounts of Hydrogen by bonding with Hydrogen and forming hydrides. (Refer figure

2.1 & 2.2)

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Figure No: 2.1

Metal hydride tank

Figure No: 2.2Metal Hydride storage unit

Hydrogen Fueled Rotary Engine_______________________________________________________________________Stored Volume : 90 standard cubic foot (2550 liters at low pressureDischarge Pressure : 30 psig (178 kPa) in ambient air, 250 psig (1.48 MPa) in hot waterMaximum Flow Rate : 1 ft3/min (28 Liters/min)Recharge Time : 4 hours in ambient air, 45 minutes in 68oF (20oC) waterVessel Material : body - stainless steel, valve - stainless steelDimensions : 24" Long by 12" High and by 3" Deep (60.96cm x 30.48cm x 7.62cm)Weight : 80 pounds (36 kg)Overpressure Protection : Rapture Disc and Relief ValvePrice : $13,500

Some alloys (in boldface in the table below) store Hydrogen at a higher density than

pure Hydrogen (even higher than the liquid Hydrogen).

MaterialH-atoms per cm3 (x

1022)% of weight that is

HydrogenH2 gas, 200 bar (2850 psi) 0.99 100H2 liquid, 20 K (-253 0C) 4.2 100H2 solid, 4.2 K (-269 0C) 5.3 100

MgH2 6.5 7.6Mg2NiH4 5.9 3.6FeTiH2 6.0 1.89LaNi5H6 5.5 1.37

Another property of Hydrogen storage alloys is that they release heat when

absorbing hydrogen and absorb heat when releasing hydrogen. This property allows their use in

heat pumps, heaters and air conditioners. So their absorption and release rates can be controlled by

adjusting temperature or pressure. The Hydrogen storage alloys in common use occur in four

different forms: AB5 (e.g., LaNi5), AB (e.g., FeTi), A2B (e.g., Mg2Ni) and AB2 (e.g., ZrV2).

Hydrogen in Internal Combustion engines

Drawbacks of conventional Reciprocating engine: High weight to power ratio,

More vibrations, Low efficiency due to reciprocating parts and valve mechanism, As Hydrogen is

highly flammable, so in case of reciprocating engine Pre-ignition is major problem, Backfiring

chances incase of Hydrogen as a fuel are more.

In Reciprocating engine during the suction stroke if the Hydrogen comes in contact

with the red hot particle or spark plug and if pre-ignition takes place then it can cause the fire in

fuel line and burst entire fuel tank

Solution to these problems is to use the Hydrogen in the Wankel rotary engine.

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Chapter No: 3 Wankel engine

Two German engineers Felix Wankel and Walter

Froed have developed the rotary engine which is

known as Wankel engine. (Refer figure 3.1)

3.1 Glossary of Terms

Apex : One of the three tips of the rotor.

Eccentric Shaft : the rotors move around it. It has sections that are offset from the center. It

supercedes the crankshaft of piston engine.

Epitrochoid : The curve that defines the inner surface of the peripheral housing is called as

epitrochoide. It is generated by rolling a circle around another circle. Perhaps should more correctly

called peritrochoid (Refer Figure 3.2).

Figure No: 3.1 Figure No: 3.2Wankel engine Epitrochoid curve generation method

Rotor : The rotor is the part of the engine that receives the power impulse of the

explosion and combustion of the fuel air mixture. It supercedes the piston of old internal combustion

engines. It sometimes loosely called a "rotary piston".

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Hydrogen Fueled Rotary Engine_______________________________________________________________________Stationary Gear : This gear is fixed to the side housing. It meshes with a gear inside the rotor so

that the motion of the rotor is constrained.

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3.2 Working of Wankel engine:-Construction & working of Wankel Rotary

engine is as in figure 3.1

Rotor having eqilaterateral triangular shape rotates in lobe shaped chamber as well as

revolve on eccentric shaft .As rotor rotates volume enclose between Rotor and chamber decreases

and increases uniformly according to its position, which causes compression and expansion of the

charge.

As 3 chamber are formed on 3 sides of rotor we get 3 expansion or power stroke for

1 revolution of rotor .There are 3 revolution of eccentric shaft i.e. out put shaft. Thus we get 1 power

stroke for each revolution of out put shaft.

Internal gear of Rotor meshes with external gear, which is fixed to casing of engine,

which regulates the motion of Rotor to maintain contact between rotor and casing. Each phase of

thermodynamic cycle occur for 900 revolution of rotor, those for 2700 revolution of output shaft.

3.3 Advantages of Rotary Combustion Engines:

The main advantage is the high power to weight ratio, Lightweight and compact,

Smooth: no reciprocating motion. Extended power "stroke" rotation of the output shaft: 270 0 vs. the

1800 of a piston, As rotor rotates, it directly opens and closes ports. So correct timing of intake and

exhaust is maintained even at high speed.

Vibration is very low because perfect balancing is possible. Smooth motion, less

mechanical losses, compactness, Cooler combustion means fewer oxides of nitrogen. Catalytic

converters lessen this advantage, Separation of combustion region from intake region is good for

Hydrogen fuel. Lower oxides of nitrogen (NOX) emissions, One stroke is of 2700 rotation of out put

shaft.

3.4 Disadvantages of Rotary Combustion Engines:

High surface to volume ratio in combustion chamber is less thermodynamically efficient. The

Wankel's long and narrow chamber makes for long flame travel, but this is countered by the Mazda's

two spark plugs (three on some racing engines). Higher fuel consumption in naive designs. This is

relative to the application because the high power of the engine must be considered.

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Chapter No: 4 Case Study

Mazda began a two-year trial period for its experimental low-pollution Hydrogen

rotary engine (RE) vehicle in 1995. The Cappella Cargo van model vehicle will burn a Hydrogen

fuel. Mazda lent the vehicle to the Hirohata Steel Mill for use as their company van and drove it for

at least 20,000 kilometers on public roads. The fuel was stored as metal hydride.

In order to evaluate the possibilities offered by the Hydrogen fueled rotary engine,

dynamometer tests were conducted with a small (2.2 kW) Wankel engine fueled with Hydrogen.

The engine was operated unthrottled and power output was controlled by quality governing, i.e. by

varying the fuel-air equivalence ratio on the lean side of stoichiometric.

The ability to operate with quality governing is made possible by the wide

flammability limits of Hydrogen-air mixtures. NOX emissions are on the order of 5 ppm for power

outputs up to 70% of the maximum attainable on Hydrogen fuel. Thus, by operating with very lean

mixtures, which effectively derates the engine, very low NOX emissions can be achieved.

The Hydrogen Miata is 400 kg (880 lb) heavier than the standard car. This is partly

because a 300 kg (660 lb) H2 fuel tank replaces the standard 50 kg (110 lb) for a full gasoline tank.

Thus it is encouraging that it performs as well as it does. Intriguingly, the prototype has a left side

driver (US). Mazda also has an electric prototype using fuel cells, also with a 400 kg increase in

weight

Gasoline Hydrogen ElectricPower (HP) 120 110

Top Speed kmh (mph) 183 (114) 150 (93) 130 (81)

0-40 kmh (25 mph) sec 2.5 2.9 4.20-100 kh (62 mph) sec 9.4 13.0 21.5

Refueling time 3 minute? 15 minutes hours?

Mazda Weighs Plans: Mazda is weighing plans to market a Hydrogen

fueled auto said to outperform electric vehicles. Mazda says timing of the launch hinges on a

government program to develop a Hydrogen fuel distribution network. Mazda claims its Hydrogen

vehicle - based on a Wankel rotary engine - has a range of 230 km and a top speed of 150 km/hr. By

comparison, the automaker says, electric vehicles typically can travel no more than 180 km without

recharging and achieve top speeds of 130 km/hr, while gasoline fueled cars have ranges as high as

590 km and top speeds of 183 km/hr.

4.1 Mazda HR-X

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Specifications of HR-X carTransmission : 4AT (EC-AT)Fuel Tank Capacity : H2: 37 Nm3

Crusing range : 200kmDimensions : 3,850 mm long x 1,700 mm wide x 1,450 mm highWeight : 1,260 kgSeating Capacity : 2 plus 2Displacement : 499 cc x 2Max. Output (net) : 100 HP at 6,500 rpm (target)Max. Torque (net) : 13.0 kgm at 4,000 rpm (target)

4.2 Test Results: Results of the trial on the Hydrogen Fueled Rotary Engine and the

conventional reciprocating engine are as follows,

4.2.1 Output power: The figure 4.1 shows the correlation between excess air ratio and

output power at 2500 rpm. Power is enhanced as the value of excess air ratio (λ) goes down. Rotary

engine functioned satisfactorily to the extent excess air ratio λ=1, and naturally achieved a high

output power. Next, Figure 4.2 shows the maximum power ratio of the Hydrogen engine to the

gasoline engine. While the Hydrogen driven Reciprocating engine (pre-mixed method) could yield

only 50% of the power attainable by gasoline specifications, the Hydrogen driven Rotary engine

achieved 63% by the pre-mixed method and 75% by the induction-cycle-injection.

4.2.2 Combustion Characteristics at Part load:

The combustion characteristics in induction-cycle-injection method Rotary engine at

part load was examined regarding indicator diagram, combustion fluctuation, thermal efficiency and

exhaust gas emission. The test were conducted at N (engine speed) =1500 rpm and Pe (BMEP) = 0.1

MPa or 0.29 MPa.

Figure-4.3 indicates the combustion fluctuation ratio. This figure shows that

Hydrogen Rotary engine gets stable combustion even if the excess air ratio (λ) is over 4.

Figure-4.4 shows excess air ratio vs. brake thermal efficiency. The maximum value

at Pe = 0.1 MPa is around λ = 3.

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Chapter No: 4

CONCLUSION

It can be concluded from this seminar that Hydrogen is the best preferred alternative

for conventional fuel in every aspect. By using Hydrogen we can develop economical and efficient

vehicle and industrial plants.

Use of Hydrogen in the rotary i.e. Wankel engine is inherently backfire preventing

and can function through a wide operating range at excess air ratio λ = 1. It was experimentally

proved that the pre-mixed Hydrogen Rotary engine achieved and O/P power up to 63 % of gasoline

specifications, while the Hydrogen Reciprocating engine with pre-mixed mixture method marked

only 50 % of gasoline specifications. Further, in case of Rotary engine, the induction-cycle-injection

could be implemented easily with an achievement of an output power of 75 % of gasoline

specifications.

When operated around excess air ratio λ = 2~3 in the partial load range, it was

proved that a high thermal efficiency together with clean exhaust gas was attainable.

One of the greatest advantages of Hydrogen as an alternative fuel is that it is they are

renewable and environmental friendly.

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BIBLIOGRAPHY

Books and Journals:

1. Mathur M. L. , Sharma R. P.,1992, ‘A Course in Internal Combustion

Engines’, “The Wankel Rotary Combustion Engine”, Ch. 23, Pg. No. 822 Dhanpat Rai

and Sons publication, New Delhi.

2. Prof. Khajuria P. R., July 1981, “Hydrogen-Fueled Spark Ignition Engine-

Its Performance and Emission Characteristics”, Ph. D. Thesis, I. I. T., New Delhi

3. H. J. Plass, F. Basrbir “Economics of hydrogen as a Fuel for Surface

Transportation” S.A.E. journal, Pg. No. 363-368

4. Kenji Morimoto, Takafumi Teramoto, and Yuji Takamori, “Combustion

Characteristics in Hydrogen Fueled Rotary Engine”, Society of Automotive Engineers

technical paper #920302 Pg. No. 479-485

Website addresses:

1. http://www.e-sources.com/hydrogen/

2. http://www.csa.com/hottopics/hydrogen/overview.html

3. http://www.humboldt.edu/~serc/generationcenter.html

4. http://www.ergenics.com

5. http://www.eere.energy.gov/hydrogenandfuelcells/hydrogen/basics.html

6. http://www.ott.doe.gov/facts/archives/fotw205.shtml

7. http://www.airproducts.com/Products/LiquidBulkGases/Hydrogen

8. http://www.enaa.or.jp/WE-NET/report/

9. http://www.nomicos.com

10. http://www.anim8or.com/gallery/gallery12/mazda.html

11. http://www.monito.com/wankel/biblio-sae.html

12. http://www.monito.com/wankel/rx-evolv.html

13. http://www-formal.stanford.edu/pub/jmc/progress/batteryswap

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106553270 Hydrogen Fuel Rotary Engine

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