Hydrogen Fuel Rotary Engine

A Seminar Report On

By

Ravindra Bhaskar Mali B.E. (MECH) [email protected] Atul Suresh Sonawane T.E. (MECH) [email protected]

Guided by: Prof. M. V. Nagarhalli

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

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.

2


_______________________________________________________________________ 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 7

3. Wankel engine

3.1

Glossary of terms

7

3.2

Working of Wankel engine

8

3.3

Advantages

9

3.4

Disadvantages

9 10

4. Case Study:

5.

4.1

Mazda HR-X car

10

4.2

Test results

10 12

Conclusion

13

Bibliography

3


_______________________________________________________________________ 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) Volume of oil discovered worldwide every 5 years (Million Barel)

250 > - 200 l i o ) f l o e r 150 e a B m n 100 u l o i o l V l i 50 M (

0 1940 1950 1960 1970 1980 1990 2000 2010 Year ------>

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.

4


_______________________________________________________________________ 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 Density Diffusivity Flame temperature Specific gravity Specific volume Properties

520 0C (968 0F) 0.08342 kg/m3 1.697 m2/hr 2318 0C (4202.4 0F) 0.6960 (air = 1) 11.99 m3/kg (191.98 scf/lb)

: : : : : :

Gasoline Diesel Methano Ethanol Natural Gas Propane Hydroge Fuel l (CNG) n

Chemical Formula

C4 to C12 C3 to C25 CH3OH

C2H5OH

Molecular Weight

100–105

200

32.04

46.07

Boiling temperature °F

80–437

370– 650

149

172

Octane no

90–100

-------

107

Freezing point 0 C

-40

Flash point, closed cup, °F

-45

Auto-ignition

257

CH4

H2

16.04

2.02

-44

-259

-423

108

112

------

130+

98

-115

-305.8

-296

-435

165

52

55

-100 to -150

-300

--

315-460

422

422

454–510

540

565-580

5

C3H8 44.1


_______________________________________________________________________ temperature, °C

6


_______________________________________________________________________ 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)

Figure No: 2.2 Metal Hydride storage unit Figure No: 2.1 Metal hydride tank

7


_______________________________________________________________________ Stored Volume Discharge Pressure Maximum Flow Rate Recharge Time Vessel Material Dimensions Weight Overpressure Protection Price

: : : : : : : : :

90 standard cubic foot (2550 liters at low pressure 30 psig (178 kPa) in ambient air, 250 psig (1.48 MPa) in hot water 1 ft3/min (28 Liters/min) 4 hours in ambient air, 45 minutes in 68oF (20 oC) water body - stainless steel, valve - stainless steel 24" Long by 12" High and by 3" Deep (60.96cm x 30.48cm x 7.62cm) 80 pounds (36 kg) Rapture Disc and Relief Valve $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).

Material H2 gas, 200 bar (2850 psi) H2 liquid, 20 K (-253 0C) H2 solid, 4.2 K (-269 0C) MgH2 Mg2NiH4 FeTiH2 LaNi5H6

H-atoms per cm3 (x 1022) 0.99 4.2 5.3 6.5 5.9 6.0 5.5

% of weight that is Hydrogen 100 100 100 7.6 3.6 1.89 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., Mg 2Ni) 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.

8


_______________________________________________________________________ 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 Wankel engine

Rotor

:

Figure No: 3.2 Epitrochoid curve generation method

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".

9


_______________________________________________________________________ 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.

10


_______________________________________________________________________ 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.

11


_______________________________________________________________________ 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 NO X 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 Power (HP) Top Speed kmh (mph) 0-40 kmh (25 mph) sec 0-100 kh (62 mph) sec Refueling time

Gasoline

Hydrogen

120

110

183 (114)

150 (93)

130 (81)

2.5

2.9

4.2

9.4

13.0

21.5

3 minute?

15 minutes

hours?

Mazda Weighs Plans:

Electric

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 12


_______________________________________________________________________ Specifications of HR-X car Transmission Fuel Tank Capacity Crusing range Dimensions Weight Seating Capacity Displacement Max. Output (net) Max. Torque (net)

4.2

: : : : : : : : :

4AT (EC-AT) H 2: 37 Nm3 200km 3,850 mm long x 1,700 mm wide x 1,450 mm high 1,260 kg 2 plus 2 499 cc x 2 100 HP at 6,500 rpm (target) 13.0 kgm at 4,000 rpm (target)

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.

13


_______________________________________________________________________

14


_______________________________________________________________________ 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.

15


_______________________________________________________________________ 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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Hydrogen Fuel Rotary Engine

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