Impact of Real World Drive Cycles on PHEV F l Effi i d C t f Diff tFuel Efficiency and Cost for Different 

Powertrain and Battery Characteristics

EVS 24M 2009May 2009

Aymeric RousseauArgonne National Laboratory

Sponsored by Lee Slezak

This presentation does not contain any proprietary, confidential, or otherwise restricted information

Project OverviewTimeline

Start – September 2009

Barriers Evaluate fuel displacement potential in 

End – September 2010

90% Complete

real world driving conditions

Budget FY09 ‐ $200K

Partners U.S. EPAFY09  $200K

FY10 ‐ $250KU.S. EPA

City of Chicago

University of California Davis

MathWorks

2

Objective: PHEV Fuel Efficiency and Cost on RWDC

Real World Drive Cycles

Analysis(Distribution)

AutomatedSizing

10

15

20

25

Spee

d (m

ph)

Drive cycle

10

15

20

25

Spee

d (m

ph)

Drive cycle

6

8

10

ence

s (%

)

60

70

80

90

100

wer

(%)

Mean=115kW

Median=100kW

Std=48kW

Distribution of Pess max discharging for each trip

6

8

10

ence

s (%

)

60

70

80

90

100

wer

(%)

Mean=115kW

Median=100kW

Std=48kW

Distribution of Pess max discharging for each trip

Motor Power for Cycle

Vehicle Assumptions

0 200 400 600 800 1000 12000

5

10

Time (s)

S

0 200 400 600 800 1000 12000

5

10

Time (s)

S

0

5

10

15

20

25

30

35

40

Spee

d (m

ph)

Drive cycle

0

5

10

15

20

25

30

35

40

Spee

d (m

ph)

Drive cycle

30

35Drive cycle

30

35Drive cycle

0

2

4

Num

ber o

f occ

ure

0 50 100 150 200 250 3000

10

20

30

40

50

Cum

ulat

ive

pow

Pess (kW)

Std 48kW

Number of trips=111

0

2

4

Num

ber o

f occ

ure

0 50 100 150 200 250 3000

10

20

30

40

50

Cum

ulat

ive

pow

Pess (kW)

Std 48kW

Number of trips=111

12

16

20

f occ

uren

ces

(%)

50

60

70

80

90

100

tive

pow

er (%

)

Mean=-32kW

Std=12

Number of cycles=290

Distribution of Pess max charging for each cycle

12

16

20

f occ

uren

ces

(%)

50

60

70

80

90

100

tive

pow

er (%

)

Mean=-32kW

Std=12

Number of cycles=290

Distribution of Pess max charging for each cycle

Battery Power

Engine Power0 500 1000 1500 2000 2500 30000

Time (s)0 500 1000 1500 2000 2500 30000

Time (s)

0 500 1000 1500 2000 25000

5

10

15

20

25

Time (s)

Spee

d (m

ph)

0 500 1000 1500 2000 25000

5

10

15

20

25

Time (s)

Spee

d (m

ph)

6

8

10

ccur

ence

s (%

)

50

60

70

80

90

100

e po

wer

(%)

Mean=123kW

Median=107kW

Std=54kW

Number of trips=111

Distribution of Pess sized for each trip

6

8

10

ccur

ence

s (%

)

50

60

70

80

90

100

e po

wer

(%)

Mean=123kW

Median=107kW

Std=54kW

Number of trips=111

Distribution of Pess sized for each trip

0

4

8

Num

ber o

-90 -80 -70 -60 -50 -40 -30 -20 -10 00

10

20

30

40

cum

ula

Pess (kW)0

4

8

Num

ber o

-90 -80 -70 -60 -50 -40 -30 -20 -10 00

10

20

30

40

cum

ula

Pess (kW)

Convergence

Yes

No

>110 TripsOne day in Kansas City 0

2

4

Num

ber o

f o

0 50 100 150 200 250 3000

10

20

30

40

Cum

ulat

iv

Pess (kW)

p

0

2

4

Num

ber o

f o

0 50 100 150 200 250 3000

10

20

30

40

Cum

ulat

iv

Pess (kW)

p

Power Split Midsize Vehicle

3

Only Hot Conditions Assumed, no Grade!

Different PHEV Powertrains and Battery Sizes

Powertrain Configuration

Battery Size PHEV Class

Power Split PHEV 4 kWh*Low Energy PHEV

8 kWh*

Series PHEV 12 kWh* High Energy PHEV

16 kWh*

4

(*) Total battery energies ‐ BOL – 60% used

10 100Distribution of Batter Energy out for Daily drives

Battery Energy Selection Based on RWDC

8

10

80

90

100

%)Mean=11 6 kWh

Series PHEV

6ence

s (%

)

60

70

nerg

y ou

t (%Mean=11.6 kWh

Median=11.1 kWhStd=6.1 kWh

PowerSplit PHEV

4

ber o

f occ

ure

40

50

ve b

atte

ry e

n

Number of Daily Drive =111DOE Requirement (11.6 kWh usable EOL ) => 51.8%

2

Num

b

20

30

Cul

umat

iv

00 5 10 15 20 25 30

0

10

Battery energy out (kWh)Battery energy out (kWh)

5

DOE Requirement (3.4 kWh usable EOL) => 10%

Several Vehicle Control Strategies Were Analyzed

4kWhLoad Following Engine Power

Optimal Engine Power

Power Split

Differential Engine Power

Load Following Engine Power

Each tuned for 10, 20, 30, 40 & 50 

miles CD range on UDDS

Study8kWh Optimal Engine Power

Differential Engine Power

Series

12kWhLoad Following Engine Power

Thermostat

Thermostat16kWhLoad Following Engine Power

Thermostat

A single control was selected in this presentation based on fuel efficiency, engine g p y, gON/OFF and Irms

6

Mean Values for the Configurations Considered

120

140

h/km

] PHEV 12 kWh Series Thermostat ControlPHEV 16 kWh Series Thermostat Control

∆2

80

100

ptio

n [W

h

PHEV 8kWh Split Optimum Engine Power

∆Fuel Consumption 

40

60

Con

sum

p

PHEV 4kWh Split LoadEngPwr 10miCD

pper added kWh Non Linear

∆1

20

40

Ele

ctric

al

ConventionalSplit HEVLinear relation between 

0 1 2 3 4 5 6 7-20

0

Fuel Consumption [l/100km]

E Electrical and Fuel Consumption

Fuel Consumption [l/100km]

7

Impact of Battery Energy on Fuel Consumption1.51.5

Conv

6.61

1

[-] 4.69

HEVSplit 4kWhSeries 

Den

sity

Series 12kWh

4.69

3.27

2.32

Split 8kWh

16kWh

0.51.5

2.32

1.23

0 1 2 3 4 5 6 7 80

8

Fuel Consumption [liter/100km]

Impact of Battery Energy on Electrical Consumption0 03

0.025

0.03 Split 4kWh

0.02

[-] Series 50 Split

Series 16kWh

0.015

Den

sity

[

111

12kWh50

86

Split 8kWh 128

0 005

0.01

0 20 40 60 80 100 120 140 160 1800

0.005

9

0 0 0 60 80 00 0 0 60 80Electrical Energy Consumption [Wh/km]

4kWh Battery Energy Provides 50% of the Gains A hi d i h 16 kWh BAchieved with 16 kWh Battery

10BaselineConv

7

8

9

ters

]

BaselineConvHEVSplit 4kWh Split 8kWhThermo 12kWhThermo 16kWh

4

5

6

el c

onsu

med

[lit

1

2

3

4

Fue

0 10 20 30 40 50 60 70 80 900

1

Distance [miles]

10

Used Battery Energy as a Function of Driving Distance

8

10

h]

Baseline ConvHEVSplit 4kWhSplit 8kWhS i 12kWh

6

8

sum

ed [k

Wh Series12kWh

Series16kWh

Same control for series independently of battery energies

4

nerg

y co

ns battery energies

For medium distance, we see largest energy consumption difference due to driving characteristics

2

Ele

ctric

al e

For short distance, we have similar electrical consumption ‐> Linked to low power demand?

-2

0

0 10 20 30 40 50 60 70 80 90-2Distance [miles]

11

Input Parameters and Assumptions for Cost A l iAnalysis

Parameter ValueEngine 300+3*Power+275*Number_cylinderHEV Battery 40 $/kWPHEV Battery 380*Total_Energy + 25*Peak_PowerElectric Machine (EM) 7 $/kWEM Controller 9 $/kWBattery Charger $800

Parameter Vehicle Cost ($)Conventional 17245HEV 20029PHEV 4kWh 21881PHEV 4kWh 21881PHEV 8kWh 23709PHEV 12kWh 27487PHEV 12kWh 29338

12

Breakeven Lines Vs. Conventionalx 104

S i

3.4

3.6x 10

Series 12kWhSplit 

8kWh

Series 16kWh

2 8

3

3.2

t [$]

2.4

2.6

2.8

Tota

l Cos

t

2

2.2 Conv

Based on Average 

0 2 4 6 8 10 12 141.6

1.8

Ti [ ]

HEVSplit 4kWh

Cost of Fuel: 4$/gal

ased o e ageFuel Consumption

13

Time [years]g

Cost of Electricity: 0.09$/kWhDistance: 12000 miles/year

Payback as a Function of Distance Vs. ConventionalConventional

18

20Break Even Lines for Different Configurations

Series 12kWh

Based on IndividualDaily Driving

14

16

[yea

rs] Series 16kWh

Split 

Fuel Consumption

8

10

12

ck P

erio

d [

8kWh

4

6

8

Pay

bac

Split 4kWh

0 10 20 30 40 50 60 70 80 900

2

4HEV

14

10 20 30 40 50 60 70 80 90Daily Driving Distance [miles]Cost of Fuel: 4$/gal

Cost of Electricity: 0.09$/kWh

Payback as a Function of Distance Vs. HEV

16

18

20

Series 12kWh Series 

12

14

16

d [y

ears

] 16kWh

8

10

12

ck P

erio

d

4

6

Pay

ba

Split 4kWh Split 

8kWh Based on Individual

0 10 20 30 40 50 60 70 80 900

2Daily DrivingFuel Consumption

15

Daily Driving Distance [miles]Cost of Fuel: 4$/gaCost of Electricity: 0.09$/kWh

Conclusions

■ Different powertrain configurations, including conventional, HEVs and several PHEVs were simulated on more than 110 real world daily drive cycles.

■ The power split configuration was selected for the HEV and PHEV 4 and 8kWh cases while the series option was used for thePHEV 4 and 8kWh cases, while the series option was used for the largest battery energies (12 and 16 kWh).

■ Significant fuel economy gains were demonstrated both with HEVs and PHEVs with fuel displacement increasing linearly with available electrical energy.

■ Benefits of adding 4kWh of battery energy seems to decrease■ Benefits of adding 4kWh of battery energy seems to decrease from 12 to 16 kWh due to the distribution of the daily driving distances.

16

Conclusions (Cont’d)

Benefits of each vehicle configuration depend on how far the vehicle is driven.  

While the electrical consumption is similar for small and long driving distance, the main differences occur during medium tripstrips.

Based on the assumptions considered (mid‐term), the cost of PHEVs remains high, requiring further research and development for batteries and electric machines.

Higher fuel prices would help too ;)

17