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PROJECT - 106 SUSPENSION SYSTEM


Project 106

"Driving m/o Ihe future chassis

Philosophy

Theory always connected to a philosophy Closed loop system thinking involving the human being! ( not open loop ) Model describing complex phenomena in simple terms


Active Safety

Vehicle-road interaction

Driver-vehicle interaction


OBJECTIVES The objectives shall satisfy SAAB's goals to produce cars with high requirements on -

individuality driving pleasure thoughtfulness performance

Road holding Maximize the tyre reaction force capacity Minimize the vertical force Variation in roll and pitch

Maximize the road holding bandwidth Low track sensitivity Low sensitivity to disturbances Ride comfort Even load distribution at all wheels Good ride comfort and isolation characteristics High load capacity Low Vibration and noise level


Handling High stability Excellent acceleration and retardation properties High total body stiffness Superior handling and active safety properties Superior cornering properties Forgiving characteristics Fast and accurate response to the drivers input Immediate and disturbance free feedback signals to the driver Oualitv and costs High reliability and long life cycle The costs for design, materials, manufacturing and Service shall be minimized within the defined cost targets When ever possible, environmentally friendly material will be selected


McPherson Suspension Benefils: Compact High integrated Low gearing Produclion cks: Friction Kinemalics spec. camber track widht alt. roll center var. etc. Vibration and noise High engine hood


Double Wishbone Benefits: Kinematics spec. camber track widht alt. Comfort properties Vibration and noise Low engine liood

iwbacks: Larger side space Costs Production


Competitors Double wishbones: GME

Opel

Senator Mercedes

S

Nissan Infinity Skyline Honda Accord Legend Toyota Lexus McPherson: Volvo Audi BMW


Suspension properties The goals are broken down to suspension properties Important properties of the suspension system are e. Road holding High lateral and vertical stiffness Low unsprung mass Equal distribution of vertical forces at the wheels Welldamped unsprung mass Good suspension system geometry Ride comfort Low center of gravity High ratio of sprung/unsprung mass Well-damped vertical body movement Tuned pitch and roll stiffness distribution Excellent medium and high frequency isolation Suspension tuned to the human being


Handling Transverse front mounted engine Neutral steered car Superior steering properties Short roll moment arm Low roll center Variation High warp stiffness Well-tuned geometrical characteristics High braking and acceleration stability No interactions between eigenmodes Low dynamic index Distinct and accurate steering wheel torque lateral force from seat break and throttel information - to the driver Oualitv and costs Quality assurance by analysis and testing Carefully selected materials for each component


GEOMETRY DATA 106

Track width

9000

1515 mm 1522 mm

� alteration Roll center height

-4/-13 mm -13/-16 mm 32 mm

10 mm

185 mm

185 mm

Camber

- 0.5 degr

- 0.7 degr

King pin incl.

12.5 degr

11.3 degr

Wheel travel

� offset Caster

50 mm 3.8 degr

offset

62 mm 2 degr

17 mm

12 mm

Toe in

1 mm

1.5 mm

Scrub radius

0 mm

7.7 mm

Tire 185/65 R15 - 215/45 R 17 195/65 R15 - 225/45 R17


Rebound (mm) Bump (mm)

Dubbla svangarmar, SAAB fram

Camber angle (degrees)


Rebound (mm) Bump (mm)

Dubbla svangarmar, SAAB fram

Toe in (mm)

Toe out (mm)


Rebound (mm) Bump (mm)

Dubblft svang&rmar, SAAB 10Q fram


Rebound (mm) Bump (mm)

Dubbla svangarmar, SAAB fram

T>;

,^| , , , , ,,

(pr, Y-'r'l

N


GEOMETRY DATA

Track width alteration Roll center height Wheel travel Camber

106

9000

1492 mm

1492 mm

2 /-15 mm

0 mm

70 mm

200 mm

200 mm

210 mm

- 0.75 degr

Toe in

7 mm

Caster

12.9 degr � offset

Scrub radius

Tire 185/65 R15

195/65 RI 5

- 0.25 degr 2.5 mm --

27 mm

-----------

7 mm

-----------

- 215/45 R 17

- 225/45 R17


074, DOUBLE WISHBONE, LOTUS (MODIFIED)

a

Rebound (mm) Bump (

ß


Rebound (mm) Bump (mm)

074, DOUBLE WISHBONE. LOTUS (MODIFIED)


Rebound (mm) Bump (mm)

074, DOUBLE WISHBONE, LOTUS (MODIFIED)


22-FTB-1990 10.42.33M

Rebound (mm) Bump (

074, DOUBLE WISHBONE, LOTUS (MODIFIED)


SAAB 9000 (1990) LOTUS 4 WHEEL DRIVETRAIN W1SHBONE REAR SUSPENSION

t


CHASSIS SYSTEM - QPTIONS A number of additional options can be selected ro the Standard equipment:

Traction Control Svstem offer good starting and hill-climbing properties especially on low and split friction surfaces allows the driver higher safety margins in split friction, rain or winter conditions at the limit of adhesion very resource efficient with a minimal addition of equipment

Four wheel drive (in Cooperation with LOTUS) a torque sensing centre differential system with fast response to torque differance torque distribution to give neutral handling properties no additional control system required automatic ABS compatibility design capacity of 350 Nm


Four wheel steer the front is steered by a power assisted rack-and-pinion steering gear the rear is steered by active eiectro-hydraulic proportional valve

the Computer controlled rear steering uses signals from accelerometers, tachometer, gyro and steering wheel angle will improve the handling properties and increase the active safety


Adaptive suspension varies the damping force of the shock absorbers uses sensor signals to change the damping force three settings : soft, medium and hard automatic ride height selection independent of load no extra fuel consumption small design modifications

Active suspension (in Cooperation with LOTUS) increases the ride comfort and the road holding properties on rough road surfaces and/or high velocity wheel bandwidth up to 30 Hz several suspension system settings possible advanced suspension system for high performance or luxury car only


ADAPTIV SUSPENSION OBJECTIVES DEVELOP AN ADAPTIV SUSPENSION THAT CLEARLY IMPROVES THE ACTIVE SAFETY (HANDLING AND ROADHOLDING) AND RIDE COMFORT COMPARED TO THE PASSIV SYSTEM.

OUR ADAPTIV SUSPENSION SHALL BE BETTER OR EQUAL TO OUR COMPETITORS, WHEN INTRODUCED, REGARDING THE FUNCTIONAL QUALITIES.

BE A PLATFORM FOR FUTURE DEVELOPMENT OF SEMIACTIVE SUSPENSIONS.

8

4

IN 9901S77 lOSr tOl 89-02


D ESCRIPTION

*

LEVELLING AT THE REAR (HYDRO-PNEUMATIC)

*

AUTOMATICALLY ADJUSTABLE DAMPING IN THREE LEVELS TO CONTROL

THE

ROLL/

PITCH

AND

HEAVE

MODE

OF

THE

CARBODY. *

TWO DIFFERENT CONTROL PROGRAMS CAN BE SELECTED "NORMAL"

*

AND

"S PORT"

CONTROL PARAMETER

FOR THE ADAPTIV DAMPING IS VEHICLE

SPEED, STEERING WHEEL ANGLE AND ANGULAR RATE/ BRAKE LIGHT SWITCH, THROTTLE ANGLE, LONGITUDINAL ACCELERATION, VERTICAL ACCELARATION AND DISPLACEMENT BETWEEN REAR AXLE AND CARBODY, *

POWER

FOR THE LEVELLING IS PRODUCED FROM AN ENGINE

DRIVEN PISTON PUMP.

*

A DIAGNOSIS PROGRAM IS INCLUDED IN THE SOFTWARE FOR FAULT MONITORING AND INFORMATION.

IN 9901577 lOS/iOi 39-02


C ONTROL

T HE

STRATEGY

BASE SHOCK ABSORBER SETTING IS

S WITCHING

TO

"M EDIUM "

OR

"HARD"

"S OFT".

IS MADE IN CASE OF

CORNERING, EMERGENCY TURNING, BRAKING, ACCELERATION OR ROAD WAVES. WHEN THE "SPORT" PROGRAM IS SELECTED ONLY THE "M EDIUM " AND "H ARD " SETTINGS ARE USED . T HE

LEVELLING IS MADE TO INITIALLY SINK THE REAR END

PARALLEL TO THE FRONT AND THEN STABILIZE IT AT A LEVEL 20 MM BELOW THE UNLOADED LEVEL.

8

4

IN 990157? (OS^Ol 89-02


SPECIFICATIONS (KEY NUMBERS)

DURABILITY :

17 YEARS/ 5000 H0URS* 300000 KM (EXCEPT FOR THE ACCUMULATORS)

RELIABILITY :

COMPARABLE TO THE ABS-SYSTEM

W EIGHT:

+ 13 KG COMPARED TO PASSIVE

COST: (PARTS ONLY) SHOCK ABSORBERS: P UMP: N UMBER

OF SENSORS :

+ 6000 SEK COMPARED TO PASSIVE (1000 CARS/YEAR)

TWO-PISTON, THREE SETTINGS, SWITCH TIME < 50 MS T ANDEM

PUMP ,

1 L/MIN


P rojekt 106

"Driving into the future" -- - chassis

philosopny

Theory always connected to a philosophy

Closed loop system thinking involving the human being (not open loop)

Model describing complex phenomena in simple terms


Flgure 1: Driver Vehicl« Ck>s«4 Leop System f-fJZCATAsy/SS? S TA S /i~ (Try

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PfC£ £• / ■

f'ö&CA f/ f

/jr- ^

y

S/<S*4t-.

- SAC*C r££0~ AS4/S£.


AUTOMATIC TRANSMISSION

MANUAL TRANSMISSION

RIGID REAR AXLE

4WS PLATFORM 106 CHASSIS/TRANSMISSION


CHASSIS DESIGN FEATURES IMPORTANT PARAMETERS TO BE TUNED INDEPENDENTLY A HIGH LATERAL STIFFNESS TUNING NOT INFIUENCING OTHER IMPORTANT PARAMETERS

D HIGH DEGREE OF CAMBER COMPENSATION TO GIVE ROAD- HOLDING

B LINEAR BUMP-STEER OVER FULL STROKE TO REDUCE NOISE FRON ROAD DISTURBMICES

E KINEMATICS AND ELASTO-KINEMATICS CHOSEN TO GIVE NO TORQUE OVERSTEER INITIALLY, AND F0R6IVIN6 CHARACTERISTICS AT LIMIT OF ADHESION

C LOU INITIAL CAMBER TO REDUCE TIRE-WEAR AND IMPROVE ROLLING RESISTANCE

F KINEMATICS AND ELASTO-KINEMATICS CHOSEN TO GIVE DESIRED STEER-EFFECTS AT THROTTLE ON-OF AND BRAKING

OTHER FEATURES LARGE FUEL TANK BETVEEN WHEELS AND IN FRONT OF THE AXLE B FUTURE ACTIVE MUFFLER SYSTEMS GIVE POSSIBILITY TO INCREASE FUEL TANK VOLUME FOR METHANOL


DESIGN FEATURES A

LONGITUDINAL KINEMATIC TO GIVE LOU IMPACT

B

KINEMATICS GIVING LONC PASSENGER COMPARTMENT FOR A GIVEN UHEELBASE

PftOJl.C.T- /OC


Comparison different platforms Design speciflcatlon

Project 106

Project

J*

Project V

BASIC CHASSIS 1. Lateral stiffness to be tuned separately from sideforcesteer 2.

a) Toe-out on bump to reduce disturbance from road irre- gularities b) Linear characteristics over full stroke

3. Low initial camber to reduce tire wear

Yes

No

No

Yes

Possible

No

Yes

No

No

Yes

No

No

3 degrees/100 mm bump

2 degrees/100 mm bump

2 degrees /100 mm hu mp

4. Camber compensation

5. Insensitive to seif aligning torque

i

Geometry chosen Yes to give no torque- steer initially but to help at limit of adhesion

ies

6. Sideforce steer to give forgiving behaviour at limit of adhesion

Yes

Yes

Yes

7. Longitudinal kinematic to give low impact

Yes

Ye s

8. Kinematics giving long passenger compartment for a given wheelbase

Yes

Light weight: Yes Fully laden: No No

No

9. Space between wheels for fuel tank

Yes

No

No

No


Comparison different platforms Design speclflcation

Projcct

Project

106

Project

V

4WD Posslble to use identical passive chassls parts as for 2WD

Yes

No

No

4WS 1.

Posslble to use identical passive C h a s s i s parts

Yes

No

No

2.

a) Posslble to use only one No actuator b) Possibility for future Yes advanced force feedback systems with two actuators

Yes

?

?

?

Same low unsprung mass as on passive car

Yes

No

No

Yes

No

No

3.

ACTIVE RIDÂŁ Posslble to easily adapt bumpsteer for active ride

4


MULTI LINK REAR SUSPENSION T-/J-CAR TOE IN CHANGE JOUNCE ----------------

MULTI LINK AXLE _____ DEVELOPMENT RANGE*

3 PASS.

.<VCONV. SEMI TRAILING REAR AXLE

/

TOE IN

IMPROVEMENTS VS SEMI TRAILING -REDUCED DEFLECTKDN

REBOUND _________________

STEER -REDUCED TIRE WEAR -TOE CHANGE WDEPENDENT FROM CAMBER CHARACTERISTIC



Project 106