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IEEE Vehicle Power and Propulsion Conference
“Spreading E-Mobility Everywhere”
October 27-30, 2014 — Coimbra, Portugal
http://www.vppc2014.org
Diverse Influence Factors on the Range of
Electric Vehicles
Alex Van den Bossche1
1EELAB UGENT Gent, Belgium
(Speaker)
Introduction
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IEEE-VPPC’14
General view, not specific for electric vehicles
Rolling losses get more
important than drag losses
around cities with low
speed and traffic jams
The weight of cars did
increase a lot in the last 50
years, but the tendency is
down again
The auxiliaries did increase
also but LEDs, improved
fans, could reverse it
Ptot = rolling loss+ drag loss + altitude increase + auxiliaries
Introduction
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IEEE-VPPC’14
Ptot = rolling loss+ drag loss + altitude increase + auxiliaries
Technical:
Altitude and kinetic energy can be partly recovered in EV and HEV
Higher efficiencies from plug to wheel
Better electric motors, transistors SiC, GaN : III-IV semiconductors
 mechanical losses get important for possible improvements
BEV driver:
From “A to B”
“range anxiety”?
Altitude, wind
= more important
ICE car driver:
“Liter/100km”
1000 km range
= average in altitude, wind
Many times A-B and B-A
Global:
CO2, resources
Rolling loss – tire life
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Rolling loss fitting
 p 

FR  M C R 
 p ref 


1.5
1.4
1.3
1.2
 0.4 1.1
x
1
y ( x) 0.9
0.8
0.7
0.6
0.5
0.5 0.6 0.7 0.8 0.9
Lifetime fitting
0.4
 p

y ( x )  1.03  3.3 
 1.1
 p ref



(Michelin)
1
x
Equations
for rolling (red)
and lifetime (blue dashed)
1.1 1.2 1.3 1.4 1.5
(Continental)
2
Collected tire-equation
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Proposed Collected tire-equation: temperature, pressure, load, tire drag: “all-in-one”
0.4
0.15


 Z 
  p 



 p 
2
 Z ref 
ref 
 c  




C R ( p,  , c )  0.85



500  
   25 


 1  0.35 tanh

 40 




1.3
1.2
Cr ( 2.1  20 80)
1.1
Cr ( 2.1 2520 80)
1
0.9
0
5
10
15
20

25
30
35
40
Effect of temperature
Influences:
- Temperature,
- Load,
- Tire pressure
- Tire drag
Tire losses: speed and temperature effects
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From Collected tire equation:
Cr ( 2.1 0 c)
Cr ( 2.1 30 c)
Cr ( 2.1 50 c)
Cr ( 2.1 70 c)
Cr ( 2.1 100c)
1.3
5
1.2
4.5
Wr ( 2.1 0 c)
1.1
Wr ( 2.1 30 c)
1
Wr ( 2.1 50 c)
0.9
Wr ( 2.1 70 c)
0.8
Wr ( 2.1 100 c)
0.7
3.5
3
2.5
2
1.5
1
0.6
0.5
4
0.5
0
0
50
100
c
Rolling resistance coefficient
Depending on speed in km/h
At different tire temperatures
150
0
50
100
c
Corresponding kWh/100km
Depending on speed in km/h
At different tire temperatures
150
Drag and wind dependency
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Drag and wind dependency
2
1
273  c  c wx 
10 5
Fd (c, c wx )  A C d  o


2
  273  3.6  3.6 10 6
15
14
13
12
11
10
Pd ( c 10 )
9
8
Pd ( c 0 )
7
Pd ( c  10 ) 6
5
4
3
2
1
0
Wind dependency of the drag losses
2m2 , 1.225 kg/m3 Cd =0.3
In kWh/100km
-- Note a factor 2 at 60km/h and 10km/h wind
at vehicle height –
- Temperature and pressure of air: not shown
Radiator drag = 2-4% of drag?
Can be minimized in electric cars
0
20
40
60
80
100
120
140
c
1
288  c  c wx 
PRa (c, c wx )  ARa C pRa o


2
  273  3.6 
3
Drag and wind dependency
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Total view
15
14
13
Wt ( 0 c)
12
Wt ( 15 c) 11
10
Wt ( 30 c) 9
Wta( 0 c) 8
7
Wh1000 6
5
Wacc ( c) 4
3
2
1
0
Total view:
Wt: total tire and drag, depending on temperature
Wta: including 200W auxiliaries
Wh1000: 1000m climbing in 100km
Wacc: acceleration, 100 times/100km without
revovery = 300 times/100 km with recovery
0
20
40
60
80
100
120
140
Radiator drag = 2-4% of drag?
Can be minimized in electric cars
c
1
288  c  c wx 
PRa (c, c wx )  ARa C pRa o


2
  273  3.6 
3
Iron loss compared to roll and drag losses
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f
c
[km/h]
50Hz
400Hz
roll
[W]
drag
[W]
roll+drag
[W]
iron
%
18
iron
/motor
[W]
32
392
45
424
15.1
144
470
3139
23520
26659
3.5
Relating roll and drag to iron losses
If PM motors are designed well,
The whole speed range van be reached at high efficiency
(constant speed without hill or accelerations)
Acceleration and hill climbing depends on copper
resistance
If M250-35A iron type is used.
PM150
Two motors?
No differential, no homokinetic coupling
Each 10kg stator iron, 10 pole, 21kW continuous, 22kg
motor, such as the PM150 [10].
Conclusion 1
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Influence
factors:
Tires
(temperature,
pressure, load,
rain),
Drag force,
(local wind,
radiator
Altitude change
Number of fast
braking items,
auxiliaries.
Conclusion 2
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IEEE-VPPC’14
Message?
Motors can be made with sufficiently low iron losses
Compared to roll and drag losses
Special attention: Auxiliaries and low speed efficiency
Major improvements in future?
Reduce weight, 3X : Roll, acceleration, hill climbing
Now 1200kg but

<3kWh/100km in ultra-light: 100kg curb weight
References
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IEEE-VPPC’14
1. REFERENCES
2. Bumin Meng, Yaonan Wang and Yimin Yang,
Efficiency-Optimization Control of Extended Range
Electric Vehicle Using Online Sequential Extreme
Learning Machine, Vehicle Power and Propulsion
Conference (VPPC), 2013 IEEE, 15-18 Oct. 2013, pp1-6.
7. Electric Car Tire Market & Technology Continental
, http://www.contionline.com/generator/www/de/en/continental/automobile
/themes/news/meldungen/2011_launch_event/download/
e_car_tires.pdf
8. Michelin Green Tires: Improving Fuel Economy and
3. T. Letrouvé, A. Bouscayrol, W. Lhomme and N. Lowering CO2 Emissions, 76th Geneva show press kit.
Dollinger, Benefits of a Double Parallel 4-Wheel-Drive 9. Worldwide light vehicle test procedure,
HEV for Different Driving Cycles, Vehicle Power and http://en.wikipedia.org/wiki/World_Light_Test_Procedur
Propulsion Conference (VPPC), 2013 IEEE, 15-18 Oct. e , read at 2014-4-30,
2013, pp1-6.
10. Data of M250-35A, material http://www.sura.se
4. Guangming Liu, Languang Lu, Jianqiu Li and
Minggao Ouyang, Thermal Modeling of a
LiFePO4/Graphite Battery and Research on the Influence
of Battery Temperature Rise on EV Driving Range
Estimation, Power and Propulsion Conference (VPPC),
2013 IEEE, 15-18 Oct. 2013, pp1-5
5. Paulo G. Pereirinha and João P. Trovão Multiple
Energy Sources Hybridization: The Future of Electric
Vehicles?, Chapter 8 of New Generation of Electric
Vehicles,
ISBN
978-953-51-0893-1,
Published:
December 19, 2012.
6. The tyre Rolling Resistance and Fuel Savings,
Publisher: Société de Technologie Michelin, Clermont
Ferrand 2003 , 122pp.
11. Data
of
PMS150,
http://www.heinzmann.com/jdownloads/electric-andhybriddrives/CAT_Electric_Drives_Product_Catalogue_e.pdf
12. Alex Van den Bossche, Peter Sergeant and Isabelle
Hofman, Towards low energy mobility using light and
ultralight electric vehicles, First International Conference
On Electromechanical Engineering (ICEE - 2012)
Skikda, 20-21 November 2012, keynote No2, 9pp.
13. Isabelle Hofman, Peter Sergeant and Alex Van den
Bossche, Optimisation of Motor and Gearbox for an
Ultra-light Electric Vehicle, FISITA 2014 , June 2-6 J,
2014 Maastricht 7pp.