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Page 1: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

1

Bio-fuels and hybrids

Prof. Wai ChengSloan Automotive Lab, MIT

Page 2: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

2

The backdrop

Page 3: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

3

Transportation and Mobility

• Transportation/mobility is a vital to modern economy– Transport of People– Transport of goods and produce

• People get accustomed to the ability to travel

Page 4: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

4

Transportation needs special kind of energy source

• Vehicles need to carry source of energy on board

• Hydrocarbons are unparalleled in terms of energy density– For example, look at refueling of gasoline

• ~40 Liters in 2 minutes (~0.25 Kg/sec)– Corresponding energy flow

= 0.25 Kg/sec x 44 MJ/Kg= 11 Mega Watts

Liquid hydrocarbons !

Page 5: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

5

What is in a barrel of oil ?(42 gallon oil → ~46 gallon products)

Source: California Energy Commission, Fuels Office

Asphalt and Road OilLiquefied Refinery GasResidual Fuel OilMarketable CokeStill GasJet FuelDistillate Fuel OilFinished Motor Gasoline

LubricantsOther Refined Products

0.90%1.50%1.90%2.80%3.30%5.00%5.40%

12.60%15.30%51.40%

Typical US output

Page 6: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

6

US Use of Petroleum by sector

1970 1980 1990 2000 20100

5

10

15

20

25

Mill

ions

of B

arre

ls/d

ay

Year

Transportation

Industrial

ResidentialCommercialElectric utilities

Source: US Dept. of Energy

Page 7: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

7

Oil Supply (annual average up to 2007)

Source: EIA

0

10

20

30

40

50

60

70

80

90

100

1960 1970 1980 1990 2000 2010

Year

Mill

ion

Bar

rels

/day

US

OPEC

Others

Hubbert peak

Page 8: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

8

The world Hubbert peak

Source: http://www.fossil.energy.gov/programs/reserves/npr/publications/npr_strategic_significancev1.pdf

(excluding OPEC & Russian production) 2003

Page 9: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

9

Petroleum price

0.00

20.00

40.00

60.00

80.00

100.00

120.00

1860 1880 1900 1920 1940 1960 1980 2000

Yom Kippur WarArab Oil Embargo

Iranian Revolution

Iran/Iraq War

Constant 2004$

$ of the day

Oil from North Sea, Alaska

Gulf War

Decrease in demand, increase in non-OPEC supply

Saudi increase production

2008 av. value up to June;

6/6/08 @$118/Barrel

$/B

arre

l

Sources: Data from EIA; event labels from WTRG Economics

9/11

Demand of emerging market; limited refinery capacity

Iraq war

Page 10: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

10

CO2 emissions from fossil fuel

1750 1800 1850 1900 1950 20000

10002000300040005000600070008000

1750 1800 1850 1900 1950 20001

10

102

103

104

YearYear

Million metric tons of Carbon/year

Total

Liquid fuel

Total

Liquid fuel

Source: EIA

Page 11: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

11

The drive to bio-fuel

• Increasing demand of liquid fuel for transportation– Population– Society affluence

• Drive for lower CO2 production• Perceived decline of petroleum reserve• Fuel price• Government Policy

– Tax credit– Required bio-fuel content

Page 12: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

12

What is bio-fuel?

Page 13: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

13

Dominant biofuels

Sugar based(corn, sugarcane, …)

Cellulosic based(switchgrass, wood, …)

Ethanol

UsageE10, E20, E85, …

Crop based(rapeseed, soybean, …)

Wasted oil/ animal fat

Algae

Bio-diesel B10, B20, ….

Compatible with current engine technology and fuel infra structure

(BTL fuel not included in this discussion)

Page 14: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

14

Example: Ethanol production from corn

Corn

Starch

Sugar

Ethanol + CO2

Ethanol fuel

By-products

Fermentation

Purification(removal of water, …)

Resources:Energy

MaterialsLabor

Page 15: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

15

Example: bio-diesel production

Soy,rapeseed, …

Oil (tri-glyceride)

Transesterification using alcohol (methanol) with alkaline catalyst

Mechanical or solvent (hexane) extraction + water removal

Esters and glycerol

Bio-diesel (esters)

Purification(removal of glycerol,

alkaline, fatty acid, …)

CH2-OOC-R1

CH2-OOC-R3

CH-OOC-R2 +3ROH ↔|

|

R-OOC-R1

R-OOC-R3

R-OOC-R2

Tri-glyceride Esters

+(CH2OH)2-CHOH

Glycerol

Resources:Energy

MaterialsLabor

(typically 8-22 C to 2 O)

AlkalineCatalyst

(KOH)

Page 16: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

16

Combustion characteristics of bio-fuel

Bio-ester data from Graboski and McCormick, Prog. Energy Comb. Sc., Vol. 24, 1998

Cetane number

s.g. LHV (MJ/kg)

LHV (MJ/L)

B10 LHV (MJ/L)

B20 LHV (MJ/L)

LHV B10/ Diesel

(by vol.)

LHV B20/ Diesel (by

vol.)

Diesel 45-55 0.820 43.22 35.44Soybean oil methylester 50.9 0.885 37.01 32.76 35.17 34.91 0.992 0.985Rapeseed oil methylester 52.9 0.882 37.30 32.90 35.19 34.93 0.993 0.986Sunflower oil methylester 49 0.880 38.53 33.91 35.29 35.14 0.996 0.991Frying oil ethylester 61 0.872 37.19 32.41 35.14 34.84 0.991 0.983

Octane number

s.g. LHV (MJ/kg)

LHV (MJ/L)

E10 LHV (MJ/L)

E85 LHV (MJ/L)

LHV E10/ Gasoline (by vol.)

LHV E85/ Gasoline (by vol.)

Gasoline 95 0.780 44.00 34.32Ethanol 107 0.785 26.90 21.12 33.00 23.10 0.962 0.673

Page 17: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

17

Stoichiometric requirement for different fuels

1 1.5 2 2.5 3 3.5 42

4

6

8

10

12

14

16

18

Fuel H to C ratio

(A/F

)st

oici

omet

ric

Gasoline and diesel

Gasoline with 11% MTBE

Ethanol

Methanol

O/C = 0

O/C = 0.5

O/C = 1

Gasoline with 10% Ethanol

E85

O/C ratios of bio-diesel esters ~ 0.12B100

Page 18: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

18

Relative CO2 production from burning different fuel molecules

C. Amann, SAE Paper 9092099

Page 19: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

19

Effects of Oxygenates on PM emission

AVL Publication (by Wofgang Cartellieri in JSME 1998 Conference in Toykyo)

Page 20: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

20

Bio-fuel combustion properties

• Bio-diesels and ethanol are fundamentally clean and attractive fuels to be used in engines

• The use of these fuels as supplements to petroleum base fuel are compatible with current engine configuration and fuel infra-structure

• Practical issues can be adequately handled by engineering– Fuel quality– Engine calibration– Materials compatibility, viscosity, …

Burning the fuel is the least of the problem !!!

Page 21: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

21

Status of bio-fuel production

Page 22: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

22

World liquid fuel production (2005)

Source: http://www.wilsoncenter.org/topics/pubs/Brazil_SR_e3.pdf

MT = Million tonsBGJ = Billions of giga (1018)Joules

HYDROCARBONS RENEWABLES

Page 23: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

23

Liquid fuel supply projection

Source: ExxonMobil – JSAE meeting, Kyoto, July 23-26, 2007

1980 1990 2000 2010 2020 2030

120

100

80

60

40

20

0Mill

ions

of b

arre

ls p

er d

ay o

il eq

uiva

lent

Page 24: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

24

US bio-fuel capacity

Yield dependent on location and weather

Crop based bio-fuels do not have enough capacity to meet the liquid fuel demand !!!

US biofuelsUS harvested crop land (US agriculture census 2002), hectareUS all distillate use (diesel+jet+power gen etc.) EIA2007; L/yrUS gasoline use, EIA 2007; L/yr

1.23E+083.34E+115.40E+11

gal/acre L/hectare

Limit of production

(gal)

Limit of production

(L)

Energy ratio of limit to demand

bio-dieselpalm oil 5.08E+02 4,756 1.54E+11 5.85E+11 1.63coconut 2.30E+02 2,153 6.99E+10 2.65E+11 0.74rapeseed 1.02E+02 955 3.10E+10 1.17E+11 0.33soy 6.00E+01 562 1.82E+10 6.91E+10 0.19peanut 9.00E+01 843 2.73E+10 1.04E+11 0.29sunflower 8.20E+01 768 2.49E+10 9.44E+10 0.27jatropia (SE Asia) 2.00E+02 1,872 6.08E+10 2.30E+11 0.64algae (?) 1.80E+03 16,850 5.47E+11 2.07E+12 5.78

ethanolcorn 3.44E+02 3,217 1.04E+11 3.96E+11 0.71sugar cane (Brazil) 8.00E+02 7,489 2.43E+11 9.21E+11 1.71

Page 25: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

25

Algae: micro-seaweeds

Issues• Production

– Need high lipid content species

– Need fast growth species

– Growth in dense environment

• Harvest techniques• Oil extraction

Courtesy of Prof. Bob Dibble, UC Berkeley

Page 26: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

26

Current largest algae plant(production of algae for salmon feeding)

Hawaii

Courtesy of Prof. Bob Dibble, UC Berkeley

Page 27: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

27

Sustainability

Page 28: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

28

Ethanol from corn• Several studies of the overall energy budget

– P = energy used in production• feedstock production/ transport + processing

– E = Energy of the ethanol output– Return (%) = (E – P) / E

• Studies– Pimentel and Patzek (2003, 2005): negative return

• Return = - 29%– USDA (Shapouri et al 2002, 2004): positive return

• Return* = +5.6%• Return* = +40% if by products (Corn gluten meal, etc.)

are accounted for

Energy balanceExample: Corn ethanol in US

* For comparison purpose, these figures were converted from the values of (E-P)/P of +5.9% and +67% in the original publication

Verdict:Substantial

environmental and economic

cost; return not clear

Page 29: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

29

Other bio-fuels

• Pimentel and Patzek also estimated energy budget for other bio-fuels. Returns:– Ethanol from switchgrass = -50%– Ethanol from wood biomass = -57%– Bio-diesel from soybean = -27%– Bio-diesel from sunflower = -118%

• Other more positive estimates:– Bio-diesel from rapeseed = +32% (EU)– Bio-diesel production = +324% (US National Bio-diesel Board)

• Outlook: NOT CLEAR– New technology needed to change the picture

Page 30: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

30

Technical difficulties of producing liquid fuel from plants

• Glucose fermentation produces significant CO2 out and energy lossC6H12O6 → 2C2H5OH + 2CO2 + 219.2 KJ-67.8 KJ -117.3 KJ - 393.5 KJ

• Cellulose much more difficult to break down than sugar

ΔHf per mol of carbon

atom

Source: Wikipedia

Glucose

Cellulose

Page 31: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

31

Effect of government policy on bio-fuel

• Current US demand for ethanol is driven by government regulations and incentives– Ethanol flex-fuel vehicles produced because of the 74%

credit towards CAFE requirement

• (E85 vehicle equivalent mph = mpg x 1.74)– Gasoline oxygenate mandate, and phase out of MTBE– Energy bill (Aug. 05) mandated a threshold of 7.5 billion

gallons (180 million barrels) production by 2012– Tax subsidy

• blender’s tax credit $0.51/gallon alcohol• $0.051/gallon fuel tax exemption for gasohol

– minimum 10 vol % alcohol

Page 32: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

32

Economic impact of crop-based bio-fuelExample: Corn ethanol in US (~20% of total corn production in 2007)

020406080

100120140160180

1992 1994 1996 1998 2000 2002 2004 2006 2008

Annual fuel ethanol production

Mill

ions

of b

arre

ls

U.S. All Grades Conventional Retail Gasoline Prices (Cents per Gallon))

0

50

100

150

200

250

300

350

400

Cen

ts p

er g

al

Jan

96

Jan

97

Jan

98

Jan

99

Jan

00

Jan

01

Jan

02

Jan

03

Jan

04

Jan

05

Jan

06

Jan

07

Jan

08

Jan

95

22.22.42.62.8

33.23.43.63.8

4

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

$ pe

r gal

lon

Fresh whole milk retail price (up to May, 08)

Annual average or averaged up to current month

Spot price 5/12/08: $ 2.50/gal

May 08 spot price: $2.50/galRetail price: $3.80/gal

Page 33: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

33

Carbon intensity(net mass of CO2 produced per unit fuel energy)

Source: http://en.wikipedia.org/wiki/Biodiesel

Page 34: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

34

Carbon intensity

Source: http://en.wikipedia.org/wiki/Biodiesel

Page 35: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

35

Other environmental impact

• Water resources• Fertilizer• Soil• Bio-diversity• Plant waste treatment

Page 36: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

36

Closure

• Bio-diesel and alcohols are excellent fuels for transportation use– Good combustion characteristics– Compatible with current engine technology

• Sustainability– Bio-fuels from crops are not likely to make any

significant impact on the global liquid fuel supply picture

• Land capacity• Effect on food price

– Further development on other feed stocks needed• Algae for bio-diesel production• Cellulosic alcohol

Page 37: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

37

Closure (continue)

• Sustainability issues– Energy budget– Water use– CO2 intensity especially with land use

replacement– Bio-diversity– Other issues

Bio-fuel plant waste treatmentResources requirement

Page 38: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

38

Hybrid vehicles

Configuration:IC Engine + Generator + Battery + Electric Motor

Concept• Eliminates external charging• As “load leveler”

• Improved overall efficiency

• Regeneration ability• Plug-in hybrids: use external electricity supply

Page 39: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

39

Hybrid Vehicles

Examples: Parallel hybrid: Honda InsightSeries hybrid: GM E-Flex SystemPower split hybrid: Toyota Prius

ENGINE GENERATOR

MOTORDRIVETRAIN

Power split Hybrid

External charging for plug-in’s Regeneration

Battery/ ultracapacitor

ENGINE GENERATOR

MOTOR DRIVETRAIN

Series Hybrid

External charging for plug-in’s

Battery/ ultracapacitor

Regeneration

ENGINEMOTOR

DRIVETRAIN

Parallel Hybrid

External charging for plug-in’s Regeneration

Battery/ ultracapacitor

Page 40: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

40

Hybrids and Plug-in hybrids

Hybrids (HEV)• “Stored fuel centered”

– Full hybrid– Mild hybrid /power assist

Plug-in hybrids (PHEV)• “Stored electricity centered”

– Blended PHEV– Urban capable PHEV– AER/ E-REV

From SAE 2008-01-0458 (GM)

Page 41: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

41

Engine/ motor sizing

0

20

40

60

80

100

120

140

160

Hybrid ConversionPHEV

Urban-Capable

PHEV

E-REVPeak

onb

oard

sup

ply/

Veh

icle

dem

and

pow

er (%

)

Mot

or

Engi

ne

Engi

ne

Engi

ne

Engi

ne

Mot

or

Mot

or

Mot

or

From SAE 2008-01-0456(Toyota)

From SAE 2008-01-0458 (GM)The optimal component sizing and power distribution strategy depend on the required performance, range, and drive cycle

Page 42: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

42

The reduced load/ speed dynamic range required from the engine offers design opportunities

From SAE 2000-01-2216 (Honda)

Honda Insight 1.0 L engine

Page 43: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

43

HEV TECHNOLOGY

Toyota Prius• Engine: 1.5 L, Variable Valve Timing, Atkinson/Miller

Cycle (13.5 expansion ratio), Continuously Variable Transmission– 57 KW at 5000 rpm

• Motor - 50 KW• Max system output – 82 KW• Battery - Nickel-Metal Hydride, 288V; 21 KW• Fuel efficiency:

– 66 mpg (Japanese cycle)– 43 mpg (EPA city driving cycle)– 41 mpg (EPA highway driving cycle)

• Efficiency improvement (in Japanese cycle) attributed to:– 50% load distribution; 25% regeneration; 25% stop and go

• Cost: ~$20K

Page 44: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

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Efficiency improvement:Toyota Hybrid System (THS)

SAE 2000-01-2930(Toyota)

A: Increase by changing operating area

B: Increase by improvement of engine

Efficiency improvement (in Japanese 10-15 mode cycle) attributed to:50% load distribution; 25% regeneration; 25% stop and go

Page 45: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

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Operating map in LA4 driving cycle

0 1000 2500 3000 3500500 1500 2000Speed (rpm)

0

2

6

4

8

BM

EP (b

ar)

BM

EP (b

ar)

0 500 1000 1500 2000 2500 3000 3500

0

2

8

6

4

Toyota THS II Data from SAE 2004-01-0164Typical passenger car engine

Page 46: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

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Cost factor

If Δ$ is price premium for hybrid vehicleP is price of gasoline (per gallon)δ is fractional improvement in mpg

Then mileage (M) to be driven to break even is

δΔ

= x P

mpg x $M

(assume that interest rate is zero)

Page 47: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

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Cost Factor

Example:Honda Civic and Civic-Hybrid

Price premium (Δ$, MY08 listed) = $7155 ($22600-15445)

mpg (city and highway av.) = 29 mpg (42 for hybrid)hybrid improvement in mpg(%) = 45%

At gasoline price of $4.00 per gallon, mileage (M) driven to break even is

miles115,00045%x 4$

29x 7155$M ==

(excluding interest cost)

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Barrier to Hybrid Vehicles

• Cost factor– difficult to justify especially for the small,

already fuel efficient vehicles• Battery replacement (not included in the previous

breakeven analysis)

– California ZEV mandate, battery packs must be warranted for 15 years or 150,000 miles : a technical challenge

Page 49: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

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Hybrid Vehicle Outlook

• Hybrid configuration will capture a fraction of the passenger market, especially when there is significant fuel price increase

• Competition– Customers downsize their cars– Small diesel vehicles

• Plug-in hybrids?– Weight penalty (battery + motor + engine)– No substantial advantage for overall CO2 emissions– Limited battery life

Page 50: Bio-fuels and hybridsweb.mit.edu/2.61/www/Good_stuff/Bio-fuels and hybrids.pdf · Dominant biofuels Sugar based (corn, sugarcane, …) Cellulosic based (switchgrass, wood, …) Ethanol

501999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

0

100

200

300

400

0

1

2

3

4

Sal

es (t

hous

ands

)

% o

f new

ligh

t dut

y ve

hicl

e sa

le

Sales figure for hybrid vehicles