TRANSPORTATION ENERGY TECHNOLOGIESsite.iugaza.edu.ps/aabuzarifa/files/ES20152_Ch8.pdfIqbal Husain,...

CHAPTER 8TRANSPORTATION ENERGY TECHNOLOGIES

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Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering

Student PresentationTopics in this Unit

Overview of transportation energyBattery‐electric vehicles (EVs)Hybrid‐electric vehicles (HEVs) Fuel cells and fuel cell vehicles (FCVs)

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Readings of Interest

Larminie, J and Dicks, J (2000). Fuel Cell Systems Explained. Chapter 2,“Efficiency and Open Circuit Voltage”. John Wiley, Chichester, WestSussex.

Burns, L et al (2002); “Vehicle of change: hydrogen fuel‐cell cars could bethe catalyst for a cleaner tomorrow” Scientific American, v287:n4, pp.60‐71. Available through CU Library System

Kreith, Frank et al (2002), “Legislative and Technical Perspectives forAdvanced Ground Transportation Systems.”, Transportation Quarterly v.56 no1 (Winter 2002) p. 51‐73 (pdf in website)

Iqbal Husain, Electric and Hybrid Vehicles: Design Fundamentals (2003).CRC Press, Boca Raton, FL.

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Some Observations about Transportation Energy Along with electricity, the “other” big target 27% of total US energy consumption in 2000 May overlap increasingly with electric generation in future

Battery‐electric vehicles Fuel cell vehicles Plug‐in hybrid electric vehicles Vehicle‐to‐grid systems

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Options for Reducing Energy Use and CO2 Emissions Shift to battery or hybrid drivetrains Shift to alternative fuels Shift to fuel cell vehicles Make systemic changes (mostly in Unit 11 on “systemsissues”) Shift passengers and freight to more efficient modes Rationalize use of transportation system

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Alternative Pathways to Carbon Emission Free TransportationName: Adopt

Battery Electric

AdoptHydrogen Approach

Innovative on-board energy storage technologies

Continue use of carbon, but offset emissions

Phase out “free-ranging”mechanized transport

Description: Carbon-free electricity provided to battery powered fleet

Carbon-free hydrogen provided to fuel cell vehicles

Carbon-free compressed air, spinning flywheels, etc.

Sequester CO2 and/or expand use of bio-fuels

Expand use of electric catenary or drastically reduce mechanized transport

Notes: 1) This list is EXHAUSTIVE (to the best of our knowledge); 2) ALL of these options are VERY challenging!

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Trend in US Energy/CO2 Levels

1

1.2

1.4

1.6

1.8

2

2.2

2.4

1970 1975 1980 1985 1990 1995 2000

Rel

ativ

e gr

owth

(197

0 =

1.00

)

FreightPassengerAll Trans.All EnergyResCommIndustrial

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US Energy Consumption by End Use 1970‐2000

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

1970 1975 1980 1985 1990 1995 2000

Ener

gy [E

J/ye

ar] Freight

PassengerAll Trans.ResCommIndustrial

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Battery‐Electric Vehicles (EVs) History

Early prototypes ca. 1900 1960s‐1970s: GM prototypes, <130km range, 130 kmh (80 mph) top speed 1990s: Saturn EV1, <150km range, 150 kmh (90 mph) top speed, very good

acceleration, approx. 1000 leased Also, growth of Limited‐Use Vehicles

GEM Limited-Use Electric Vehicle

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EV Powertrain Note that source charger is not onboard vehicle Modern EVs convert DC to AC

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Some Vehicle Design Considerations Same criteria apply to EVs and HEVs as to ICEVs

Maximum Range: distance between refueling (for ICEV) or recharging(for EV)

Maximum Gradability: steepest incline that the vehicle can climb at agiven speed

Maximum Velocity Maximum Acceleration (e.g. time to go from 0 to 100 k/h)

Example: Saturn EV1: Curb weight: 920 kg plus 400 kg batteries Lead‐acid batteries: 55 wh/kg, ~$125/kwh Charge requirement: 0.206 wh/kg‐km

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Maximum range for a representative lead‐acid battery EV in km on a single charge, as a function of mass of batteries installed

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Vehicle cost as a function of range for EV

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Overview of Hybrid Vehicles (HEVs) 1970s: first standards for HEVs published by USDOE First on US market was Honda Insight (1998) Currently marketed by many major makers in US market, elsewhere Combines best features of ICE and EV technology:

High energy density, long range of ICE High starting torque, low emissions of EVs

Currently emerging: “plug‐in” hybrids w/ 20 or 60 mile electric range

2005 Toyota PriusCourtesy of philglaserphotography.com

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Growth in US Hybrid Sales 1999‐2006

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Hybrid‐Electric Drivetrain Design

Source: Kreith et al (2002)

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Use of Atkinson Cycle in HEVs Type of ICE used in Prius, Ford Escape Cycle invented by James Atkinson in 1882 Optimizes efficiency at the expense of power Two alternatives for implementation:

1. All 4 cycles of 4‐stroke engine happen in single revolution ofcrankshaft: greater expansion ratio than compression ratio

2. Intake valve is held open longer, effectively reducing compression /increasing expansion

>> See animation at http://www.keveney.com/Atkinson.html ; alsohttp://en.wikipedia.org/wiki/Atkinson_Cycle

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Comparing Toyota Prius to VW Diesel Jetta, Toyota Echo

[kg] City Hwy OverallPrius 1258.5 45 52 48.5Echo (auto) 956.8 33 39 36Echo (man) 926.8 35 43 39

Eng Size MaxPr Power/L Economy [MPG]cc [kW] City Hwy Overall

Prius 1500 42 28.0 45 52 48.504 Prius 51 60 55.5Jetta 1900 67.05 35.3 41 49 45

Compare to VW Jetta Diesel

Compare to Toyota Echo Gasoline ICEV

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“Take‐home points” on electric & hybrid vehicles1. The weakness of the EV is the cost and weight of batteries.

– new battery technology is becoming lighter and cheaper– In the future, EVs may be able to break into markets where costs are

currently prohibitive

2. HEVs can compete for market share by compromisingbetween EVs and ICEVs

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Reasons for Interest in FCVs1. Greater potential efficiency than internal combustion engine (ICE)2. Eliminate emissions at the tailpipe3. Allow a wide range of initial energy sources, including non‐fossil

and renewable4. Allow more flexibility in vehicle design5. Easier to store/distribute hydrogen than electricity

Prototype Fuel Cell BusUniversity of Delaware, 2008

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Figure 13‐14. Schematic of hydrogen fuel cell function, showing anode, cathode, and proton exchange membrane

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Figure 13‐15. Exploded view of a fuel cell stack, made up of alternating units of fuel cells and bipolar plates

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A New Vision for Fuel Cell Vehicles Most current fuel cell vehicles are retrofitted ICEVs In the future, FCVs might be designed from the ground up

Energy is transmitted from the fuel cell to the wheels usingelectricity

No fixed draft shaft, transmission, etc. More flexibility about how to lay out vehicle

Example GM “HyWire” fuel cell concept car

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Practical Consideration of Fuel Cell Efficiency Nernst equations provide theoretical model of performance

Are most accurate at high temps At low temps, benefits of raising pressure are greater than predicted

Not captured by Nernst equations: , , are partial pressures of H2, O2, and H2O, resp. Decline in , , rise in as H2, O2 move thru FC, leads to decline in current

density Tradeoff between high throughput and high efficiency

In general actual efficiency is well below predicted maximum, due tolimitations in materials technology”

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TRANSPORTATION ENERGY TECHNOLOGIESsite.iugaza.edu.ps/aabuzarifa/files/ES20152_Ch8.pdfIqbal Husain,...

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