Torque Vectoring for improved vehicle · PDF filefor improved vehicle dynamics Vehicle...

1 BEG-CD | 6/22/2010 | © Bosch Engineering GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.

Bosch Engineering GmbH

Peter van Vliet Bosch Engineering GmbH

Torque VectoringTorque Vectoringfor improved vehicle dynamicsfor improved vehicle dynamics

Vehicle Dynamics EXPO Stuttgart, June 22nd 2010

2


BEG-CD | 6/22/2010 | © Bosch Engineering GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.


► 100 % subsidiary of Robert Bosch GmbH► established in 1999, approx. 1400 employees► customized solutions based on Bosch products

CombustionEngines

CombustionEngines

Vehicle Dynamics

Vehicle Dynamics

EE-Integration

EE-Integration MotorsportMotorsport Sensor-

Systems

Sensor-Systems



Torque Vectoring – Actuators

active differential

Differential

brake

Brake

electric motor

E-Motors

yaw torque yaw torqueyaw torque



Contents

driver

unique benefits regarding lateral

dynamicsless compromises

raise performance objectively

unique benefits regarding vehicle

dynamics


dynamics



ESC

TV brake

understeering oversteering

Torque vectoring – range of action

TV electric motors

ESC

TV differential

TV brake

dynamic state of the vehicle

6

Raise the limiting cornering speed



60

friction potential is notutilized completely

without torque vectoring- understeering setup -

front axle reaches the limit first

with torque vectoring- neutral -

yaw torque reduces lateral slip at front axle

increased usage of friction potential at rear axle

limitingspeed

60

limit not reached

7

Raise the limiting cornering speed



60

friction potential is notutilized completely

without torque vectoring- understeering setup -

front axle reaches the limit first

Full usage of friction potential

70

with torque vectoring- neutral -

Improvement of traction!

limitingspeed

limitingspeed



without torque vectoring

with torque vectoring

steering angleyaw rate

time

steering angleyaw rate

time

Virtual reduction of the moment of inertia



Contents

driver





dynamics

10

The compromises in chassis tuning



Torque vectoring alternativeslower center of gravity

Benefit► less load transfer improves traction and

agility

Compromises► chassis needs to be adapted

► stiffer springs affect comfort

► less ground clearance

torque vectoring

Benefits► torque vectoring does not affect

driving comfort

► chassis tuning can be focused more

on aspects like comfort and stability,

since agility and traction are already

improved

11

The compromises in chassis tuning



Torque vectoring alternativesincreased camber angle at front wheels

Benefit► more grip at front axle: increased agility

Compromises► loss of driving stability at high speeds

► no vehicle dynamics control

► tire wear

torque vectoring

Benefits► agility improvements are situation

dependent (sensor information)

► agility at low speeds, simultaneously

stability at high speeds

► adaptive control on dry or wet

asphalt and low-μ



Contents

driver





dynamics

13

Coupé (Bosch Engineering)

► torque vectoring actuator: 4 e-motors

► total power: 4 x 60 kW

► maximum wheel torque: 700 Nm► acceleration 0-100 km/h: ca. 7 s

► maximum speed: 130 km/h

► weight: 1970 kg► battery capacity: 45 KWh

Experimental results – TV e-motors and TV-brake



Sports car (OEM)

► torque vectoring actuator: brake

► combustion engine power: > 350 kW

► maximum speed: > 250 km/h► weight: ca. 1550 kg

► driven wheels: rear axle

14

Speed differenceseveral attempts to find out maximum drive-through speed

TV e-motors: 70 km/hno TV: 66 km/h

cone distance = 18m

Experimental results – E-motors – slalom course



-40 -20 0 20 40-200

-150

-100

-50

0

50

100

150

200

yaw rate [rad/s]

stee

ring

whe

el a

ngle

[°]

TV e-motorsno TV

15

radius = 50m

speedslowly increasing until the vehicle leaves the circular path

Experimental results – brake - skid pad testing



50 60 70 80 90 100 110 120

6789

101112

Steering wheel angle (°)

late

ral a

ccel

erat

ion

(m/s

2 )

TV - brakeno TV

1 m/s2



Experimental results – brake – race track driving

lap distance: 2.2kmnumber of laps: 2lap times reproducibility: < 0.2s

17

100

120

140

160

180sp

eed

[km

/h]

02040

brak

e [b

ar]

600 700 800 900 1000 1100 12000

50100

thro

ttle

[%]

distance [m]




TV brakeno TV

driver brakes earlier due to higher speed

earlier on-throttle at corner exit

speed level is raised by TV

18

100

120

140

160

180sp

eed

[km

/h]

02040

brak

e [b

ar]

5600 5700 5800 5900 6000 6100 62000

50100

thro

ttle

[%]

distance [m]




Lap time reduction lap 1:

Measured improvement of lap times

1.1 seconds

Lap time improvement by torque vectoring strongly depends on:

► Chassis setup of vehicle (this case: understeering)

► Engine capacity: possibility to maintain the speed offset after corner exit (this case: > 350kW)

► Capability of the driver to push the vehicle to the limit (this case: world class driver)

Remember that Nordschleife is 21km…

Lap time reduction lap 2: 0.95 seconds

Lap distance: 2.2 km

19

Conclusion



Torque vectoring

► Improvements in agility, safety, traction

► Chassis tuning without compromising on stability or comfort

► Benefits can be measured objectively

► Proven maturity of brake actuation concept

► Extended opportunities in multi-motor electric vehicles

--- An efficient method to improve vehicle dynamics ---

Thank you for your [email protected]

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