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8/9/2019 Hydrogen No Animation

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Hydrogen Automotive

Power


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Hydrogen Internal Combustion Advantages

H2 has a high specific energy(energy

per unit mass) (8)

Higher than liquid hydrocarbons by a

factor of 2.8(8)

Very easy to burn (8)

Main by-product is water vapor (4)


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Hydrogen Internal Combustion Advantages (contd)

Can be operated as diesel engines at very lean air-fuelratios and high compressions (15)

Spark ignited, but load variations are achieved using WOT(wide-open throttle) by varying the richness of the hydrogen-air mixture. (15)

The throttle valve can be omitted because H2 has broad

flammability limits (15)

Lower limit = 4% (15)

Upper limit = 75% (15)

Extremely lean mixtures during idle run leave a highconcentration of unburned H2 (up to 3% by volume), which poses

a safety problem.(15)

Can be addressed by a compromise, using a throttle valve

during idle run and WOT with variation in the mixturesrichness in all other cases. (15)


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Hydrogen Internal Combustion

Disadvantages Less horsepower (4)

Shorter driving range (4)

H-ICEs use 3.5 times more liquid H2 than gasoline(9)

H2has a very low energy density(energy per unit volume)(8)

Liquid H2 has less energy density than aviation kerosene by a factor of

about 4.1 (8)

Consequently provides less energy per storage space (12)

Requires higher volume for the same amount of energy (13)

Traces of NOx generated by high-temperature reactions

of atmospheric N2 & O2 during combustion(8)

Can be cleaned up by catalytic converters (9)

Leaner air-fuel mixtures reduce combustion temperature but lowerhorsepower (9)


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Hydrogen Internal Combustion

Disadvantages (contd) Backfire is a major problem for H-ICEs (15)

The air-fuel mixture can ignite before IVC(intake valve closure), causing an

explosion in the intake manifold(15)

Caused by hot spots in the combustion chamber(15)

Residual gases (15)

Surface deposits (15)

Valves(15)

Use of a lean air-fuel mixture eliminatesbackfire but decreases power output (15)


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Fuel Cells

Fuel cells break apart a molecule of H2 intoelectrons & protons (5)

Two plates are connected by a wire with an electrolytesandwiched in between (13)

Hydrogen is supplied to one plate, and oxygen to the other (13)

The two elements are attracted to one another and try to bond(18)

Only the proton of the hydrogen atom can pass through themembrane in the sandwich (18)

The accompanying electron of this proton has to go around themembrane, passing through a coil and creating electricity. (18)

The hydrogen proton and electron reunite with oxygen on the otherside of the membrane, creating water and a small amount of heat(18)


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Fuel Cells

Advantages Combine the best of batteries (quiet, no emissions)

and ICEs (easy refueling once the infrastructure is inplace) (18)

Far more energy-efficient than gasoline-fueled

vehicles

(1)

Have double the efficiency of ICEs (13)

Far less polluting (1)

Simple construction (13)

Mass production costs would become extremely low (13)

10-fold increase in power density of fuel-cell stacks & 10-fold

decrease in their cost within the past 5 years (19)


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Fuel Cells

Disadvantages Expensive (1)

Prototype fuel cells last only 1/5th as long as wouldbe needed to make fuel cells cost-effective (5)

Energy losers (5) Costs more to produce hydrogen than is earned

by using H2 in fuel cells(5)

Electricity generated by fuel cells in cars coststhousands of dollars per kilowatt (5)

Would have to fall by a factor of 10 to becomeeconomically viable (5)


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Hybrids

A proven technology that couldincrease fuel-economy 50% (2)

The electric motor gets the car started andup to speed. (14)

As the car slows down, kinetic energyrecharges the battery. (14)

Never need plugging in (2)

Combine the advantages of

batteries, electric motors and ICEs.(13)


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Hybrids

2 Types:1. Electric motor to drive the wheels with a

small engine to drive a generator whichcharges the batteries. (13)

2. Parallel Hybrid (13)

Allows either the engine or electric motor todrive the wheels. (13)

Uses the engine only at optimum speed. (13)


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Hydrogen Safety

The Hindenberg Phenomenon H2 gas is highly explosive

(4)

One of the most flammable

substances on Earth. (12)


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Hydrogen Safety (11)

.30 caliber armor-piercing bullet fired from 50 w/o fragmenting

Livermores hydrogen cryogenic tank, thus meeting DOT & SAEstandard (11)


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Hydrogen Production

Two methods Electrolysis (7)

Requiring H2O & electricity(7)

90% of electricity produced in the U.S. generated by fossilfuel plants that emit CO2

(7)

Reforming (7)

Requiring a hydrocarbon which is mixed with H2O & heat(7)

Releases CO2(7)

An on-board reformer can produce H2 from a liquid fuel

(methanol or gasoline) (13)


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Hydrogen Production

Expensive to produce(7)

1,600 joules required to produce an amount of H2yielding only 1,000 joules (7)

Only 167 joules required to produce an amount of gasolineyielding 1,000 joules (7)

Can produce greenhouse gases(3)

In the long term, wind energy can pluck hydrogenfrom water in the ocean (3)

In the near term, more likely to come from natural gas(3)

Right now, the cheapest and most efficient way tomake hydrogen is to reform the carbon in natural gas.(14)


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Hydrogen Storage

Gas in pressurized tanks (17) Very heavy (17)

A safety tank holding 3 kg (6.6 lbs) of H2 would

weigh 400 kg (880 lbs), cutting into fuel economy(17)

Gas can migrate into the metal, making themetal brittle, fatiguing it so H2 can leak from

the tank (17)

Quantuum Technologies of Irvine, CA, addressesthis problem with a carbon fiber impermeable liner(17)


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Hydrogen Storage

Liquid in cryogenic tanks(17)

Low temperature of liquefaction: -253 C (8)

Liquefaction is very expensive (9)

High electrical consumption is required to liquefy H2(17)

Evaporative losses occur (17)

2% of liquid H2 is lost to evaporation per day (9)

Less dense than other liquids

Very low energy density(energy per unit volume) (8)

Liquid H2 has less energy density than aviation kerosene by a

factor of about 4.1 (8)

Consequently provides less energy per storage space (12)

Requires higher volume for the same amount of energy

(13)

Liquid H2 requires high degree of thermal insulation(8)

Adds to weight and cost of storage tanks (8)


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Hydrogen Storage

Solid in metal hydrides(17)

H2 is chemically bonded to alloys(17)

Heat is required to release the H2(17)

Compact (17)

1/3 the volume of a pressurized H2 gas tank at 5,000 psi(17)

the volume at 3,600 psi (17)

Inherently safe (17)

Held at low pressure (less than 200 psi) (17)

At ambient pressure (17)

In the event of a crash, hydrides do not release H2(17)

Very heavy(17)

A metal hydride system holding 5 kg (11 lbs) of H2 would

weigh 300 kg (660 lbs) (17)


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Hydrogen Storage Millennium Cells H2-On-Demand

(6)

Stores H2 in the form of sodium borohydride (NaBH4)(6)

Soap-like chemical used for bleaching paper (6)

Can be stored as a liquid in plastic containers under ambienttemperature and pressure (6)

Neither flammable nor explosive (6)

Waste product is borax (NaBO

2

) (6)

Removed from the car while fresh NaBH4 is pumped in(6)

Waste borax is easily recycled to create NaBH4 by adding H2(6)

Catalyst liberates H2(6)

No separate H2 storage needed(6)

Can deliver H2 at 100% humidity

(6)

Humidity levels are critical for fuel cell health (6)


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Millennium Cells NaBH4/NaBO2 Flow(6)

(Sharke, Mechanical Engineering, 2/02)


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Millennium Cells NaBH4/NaBO2 Loop(6)


Mill i C ll N BH /N BO St


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Millennium Cells NaBH4/NaBO2 Storage

Tank (6)



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Prototypes ICE Prototypes

BMW has tested about 20 H-ICE prototypes over the past 20 years (9)

220-mile range vs. 370-mile range for gasoline version of the 750hL (9)

BMWs ICE prototype buries fuel lines in the chassis (10)

Sensors detect any trace of H2 and cause windows and trunk lid to open

immediately (10)

Developed dual-fuel capability ICEs until H2 refueling stations become

common (9)

FCV Prototypes GM Hy-Wire (combines fuel cell power with drive-by-wire) (20)

Ford Focus: 15 cars in various stages of testing(20)

Chrysler Natrium (uses sodium borohydride) (20)

Toyota Highlander: 2 on University of California campuses (20)

Honda FCX: 5 leased to the city of Los Angeles (20)

Nissan Xterra: part of Californias Fuel Cell Partnership Program (20)

Hybrid Prototypes

Toyota has sold 125,000 Prius hybrids since 1997. (14)


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References

1. Hydrogen-Fueled Vehicles: Why Wait Sixteen Years? PR Newswire, 1/31/03

2. A Bad Element, Robert F. Kennedy Jr., NYT, 2/16/03

3. Our New Hydrogen Bomb, Nicholas Kristof, NYT, 2/21/03

4. Mazda Motor Takes Journalists for Jaunt In a Hydrogen Car, Michael Williams, WSJ, 10/25/93

5. The Burning Questions of Hydrogen, The Washington Times, 11/10/026. Better Storage Through Chemistry, Paul Sharke, Mechanical Engineering, 2/02

7. Hydrogen Isnt Yet the Miracle Fuel of the Future, George Burman, The Fresno Bee, 1/25/03

8. Fuel-Related Issues Concerning the Future of Aviation, F. Armstrong, J. Allen, & R. Denning, Journal of AerospaceEngineering, Vol. 211, No. 1, 2/24/97

9. Another Take on Hydrogen, Joerg Dittmer, Canadian Business and Current Affairs, 2/17/03

10. R & D in the Fast Lane, Bill Siuru, Mechanical Engineering, 2/89

11. Filler Up With Hydrogen, Michael Valentini, Mechanical Engineering, 2/02

12. Hydrogen Cars Spark Fuel Debate, Mark Nolte, The Daily Universe, 2/12/03

13. Mobile Technology: Focus on Transport, Energy and Environmental Management, 11/0214. The Green Car, Rose Simone, Toronto Star, 2/15/03

15. Experimental Study of a Hydrogen-Fueled Engine, R. Sierens and S. Verhelst, Journal of Engineering for GasTurbines and Power, Vol. 123, 1/03

16. Hydrogen-Powered Bus Hits Streets, Greg Paula, Mechanical Engineering, Vol. 119, Issue 8, 8/97

17. Filler Up With Hydrogen, Michael Valenti, Mechanical Engineering, Vol. 124, Issue 2, 2/02

18. H2GO: Hydrogen-Powered Cars the Wave of the Future, by David Arnold, The Boston Globe, 11/5/02

19. Vehicle of Change, Lawrence Burns, Byron McCormick, and Christopher Borroni-Bird, Scientific American, Vol.287, Issue 4, 10/02

20. Imports Invited to Bush Fuel Cell Party, Harry Stoffer, Automotive News, Vol. 77, 2/10/03

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