wheelhub integration of electric motor in fse

8/11/2019 Wheelhub Integration of Electric Motor in FSE

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Workshop 2011Electric Powertrain


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Introduction

Name: Robert Weingart

Course of study: automotive engineering

focus: combustion engines

Team: WHZ Racing Team

Zwickau

Career in FS: season 2010: team engine

season 2011: team power train

season 2012: team leader power train


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Structure of Presentation

1. Targets of Development

2. Preliminaries

3. Electric Motor4. Wheel Hub Integration

5. Problems

6. Summary


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2. Preliminaries


5. Performance

6. Problems

7. Summary


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Targets:

electric drive allows independent drive of each wheel

helps to improve vehicle dynamics

extra power through front wheels better performance in slippery conditions

increases recuperation from brake energy


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Important Facts of Development:

keep additional weight low

maximize the efficiency

integration in wheel hubs control the power by torque vectoring

minimize additional inertias (z-axis, steering)


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2. Preliminaries


5. Performance

6. Problems

7. Summary


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Investigation

additional weights at the front axle with regard to:

moment of inertia

unsprung masses

weight transfer through acceleration

transferable forces (x-direction) limited by wheel load (F_z)

use of tire data diagram


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Investigation

calculation of additional weight per wheel:

increases the inertia (around z-axis) by J=5,85 kgm per wheel

part weight [kg]

motor (rotor + stator) 2,8

gearbox 1,0

drive shaft 0,6

rpm-sensor 0,1

hub/ upright 0,8

bearing 0,1

housing 0,6

= 6,0 kg


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Validation

test drive with additional masses (2x 6,0kg):

located in the wheel hubs/ in the center of gravity

track:

skid pad

slalom parcours (section like autoX)

results:

equal lap time at skid pad

slower time at slalom parcours

slower behavior of the car while steering


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Recuperation

reference lap from endurance 2010 of combustion car with

P=58kW

calculation of needed energy/ possible regenerating from

brake energy

detailed look at negative power

note dynamic weight transfer to front axle


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Power Chart ofFSG10 AX

power[kW

]

-80

-60

-40

-20

0

20

40

60

80

time [s]

0 5 10 15 20 25 30 35 40 45 50 55


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Possible Recuperation

s

kW

limited performance for energy recovery on the front axle

limited performance for energy recovery on the rear axle

limited performance for energy recovery of the vehicle

power[kW]

-60

-50

-40

-30

-20

-10

0

time [s]

0 5 10 15 20 25 30 35 40 45 50 55


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2. Preliminaries

3. Electric Motor

4. Wheel Hub Integration

5. Performance

6. Problems

7. Summary


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Motor

high speed motor from industrial sector

normally used for machining tools

lightweight motor with high rpm

designed as a support drive

integrated temperatur sensor

external rpm-sensor


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2. Preliminaries

3. Electric Motor


5. Performance

6. Problems

7. Summary


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Different Concepts of Final Drive

criterias

weighting factor

Varianten

planetary gear spur gear

fi fj f=fi*fj p p*f p p*f

a. energy

0,7

/ / / / / /

efficiency 0,4 0,28 3 0,84 2 0,56

weight 0,3 0,21 2 0,42 1 0,21

wheel bearings 0,3 0,21 3 0,63 3 0,63b. inertias

0,1

/ / / / / /

steering axis 0,4 0,04 2 0,08 1 0,04

z-axis 0,4 0,04 2 0,08 3 0,12

rotating masses 0,2 0,02 3 0,06 1 0,02

c. manufacturing

0,2

/ / / / / /

assembling effort 0,3 0,06 2 0,12 1 0,06

tolerances 0,2 0,04 2 0,08 1 0,04

number of parts 0,2 0,04 2 0,08 1 0,04

complexity 0,3 0,06 2 0,12 1 0,06

total 1 / 1 / 2,51 / 1,78

changeable cells x x x x


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Comparison of Both Concepts

spur gear planetary gear


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Scheme of Front Motor Unit

stator

rotor

electric motorplanetary

gear

sensor


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Further Tests

investigation of connectors for

cooling system

buckling test by simulating a

reference lap from FSG

different hoses with different

buckling protections were tested


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Buckling Test


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Before Assembly

overview of all parts flanges and shafts


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2. Preliminaries

3. Electric Motor


5. Performance

6. Problems

7. Summary


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Load Spectrum

values of torque from control unit show distribution during

FSG11 autoX

long time at full load,

zero load during cornering

improved performance in

rainy conditions

(FSUK11 and FSG11 EN)


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2. Preliminaries

3. Electric Motor


5. Performance

6. Problems

7. Summary


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Perfomance while ACC

low efficiencies (gearbox, sealings, bearings, )

errors from control unit/ converter motor switched off

0,00

0,25

0,50

0,75

1,00

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5

P[kW]

t [s]

efficiency at FSG11 ACC

P_mech_fl/P_el_fl

P_mech_fr/P_el_fr


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t1:40 3:20 5:00 6:40 8:20 10:00 11:40 13:20 15:00 16:40 18:20 20:00 21:40 23:20 25:00 26:40 28:20

km/h

0

7.5

15

22.5

30

37.5

45

52.5

60

67.5

75

82.5

90

C

0

25

50

75

100

125

150

175

Temperatures

T=150C

T=120C

velocitytemperature water temp.

current


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2. Preliminaries

3. Electric Motor


5. Performance

6. Problems

7. Summary


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Summary

support drive at front axle in small installation space

possible improvement of performance by torque vectoring

high recuperation ability

additional weight of 30kg (motors, lines, batteries, )


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See you at Hockenheim

01. 05. August 2012

wheelhub integration of electric motor in fse

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