0.80

0.85

0.90

0.95

1.00

1.05

1.10

A B CProving ground

PF

C v

alue

(A

ST

M11

36)

Comparison between K value and PFC value on Dry surface

Fig. 1 ： Friction Coefficient between typical proving ground

Fig. 2 ： The Ratio of K-value to PFC value for passenger cars

0.8

0.9

1

1.1

1.2

1.3

1 2 3 4 5 6

(K v

alue

)/(P

FC

val

ue) Proving

Ground AProving

Ground BProving

Ground C

: PFC (ASTM1136) = 195/75R14 （ M/L Tiger Paw)=

: K value (1~ 6; different vehicle)

1; 225/50R182; 215/65R16(M+S)3; 175/65R14(AS)4; 205/55R165; 215/45R176; 205/50R17

The surface friction difference between proving ground is small.(A-C: 6%)K-value shows higher than PFC.The difference depends on thetyre performance.

GTR-ESC-2007-10-A1 (1)

1. Contents of Study:

- The comparison of lateral displacement on the different surface friction coeff. (0.8, 0.9, 1.0) by using simulation of the Sine with Dwell test without ESC operation was done by several Japanese car manufactures. (condition: Vehicle speed; 80 km/h, Steering wheel angle; 5x(0.3G steer angle))

Lateral Displacement Influenced by Surface Friction(1)

Vehicle

Wheel Base Weight Tyre

FR P-car ：ASUV ： LFF P-car ：BSUV ： MFF P-car ：C SUV ：

NFF P-car ：DSUV ：

OFF P-car ：E SUV ：

PFF P-car ：F SUV ：

QSUV ：RFF P-car ：

G

A

B

C

D

E

F

GH

153319911570169015202280165921721375151514001700

9581896

205/55R16235/55R18205/50R17205/60R16215/50R17245/50R20215/55R17265/50R20235/45R17225/55R18215/45R17215/55R17

175/65R14225/65R17

273027202700290027302880

2635267026202620

24402640

27752850

Simulation software

CarSim

In-house soft

veDYNA

CarSim

ADAMS/Car

ADAMSADAMS

In-house soft

[mm] [kg]

(2)

Lateral Displacement Influenced by Surface Friction(2) 2. An Example of time history data (Passenger Car)

-0.5 0 0.5 1 1.5 2 2.5 3 [s]

[deg]120

0

-120

1.07

Ste

eri

ng

Wh

eel

An

gle

[m/s ]

10

0

-10

2

SWA[deg] = 　 0.8= 　 0.9= 　 1.0

Lat

eral

　A

ccel

erat

ion

-0.5 0 0.5 1 1.5 2 2.5 3 [s]

Fig 3 ： Time history data of passenger car

[m]6

0

-6

Lat

eral

　D

isp

lace

men

t

-0.5 0 0.5 1 1.5 2 2.5 3 [s]

SWA[deg] = 　 0.8 = 　 0.9= 　 1.0

The influence of surface friction to thelateral displacement is small, because

and are canceled each other.

μ =0.8μ =0.9μ =1.0

0.9 1 1.1 1.2[s]

2.94

2.74

-2.0

-3.5

[m]

(3)

Lateral Displacement Influenced by Surface Friction(3)

3. All results

1.5

2

2.5

3

3.5

0.8 0.9 1Friction coefficient ()

Lat

eral

dis

pla

cem

ent

[m]

Fig 4 ． The influence of the surface friction to the lateral displacement

P-car : AP-car : BP-car : CP-car : DP-car : EP-car : FP-car : G

SUV : LSUV : MSUV : NSUV : OSUV : PSUV : QSUV : R

Ave. difference: 15cm @0.9 - @0.8 = 18 cm @1.0 - @0.9 = 13 cm

(4)

= Reference : The testing error range (1)=

22 [cm]

∫∫AY

CG

・d

t・

dt

@ 1

.07s

　[m

]

5 1 2 3 4 6 7 8 9 10

The tyre lot No.

2.5

2.4

2.3

2.2

2.1

2.0

Fig 5 ． An Example of the error range of driving test by different lot number of tyres

(5)

“Lateral Displacement” for SWAN > 5• Least sensitivity to temperature (ΔT = 489 for 302)

• High S/N (11.0)

• 4 significant track differences

AZ CA MI OH SC2.6

2.8

3

3.2

3.4

3.6

3.8

4

Track

min

(ayc

g_i

nt_

int_

1p0

7_fs

) fo

r sw

an

> 5

302: 3 Sig. Diff. by Track, M32: 1 Sig. Diff. by Track, S/N = 11.0

302M32

0 20 40 60 80 1002.6

2.8

3

3.2

3.4

3.6

3.8

4

Final Ambient Temperature (deg F)

min(aycg_int_int_1p07_fs) for swan > 5

302 R=-0.74; Slope = -1.21e-003; T = 489M32 R=-0.34

From NHTSA docket:No. 25801-9

= Reference : The testing error range (2) = (6)

20cm18cm

18cm