GTR-ESC-2007-10-A1 (1)
PFC value (ASTM1136)
Comparison between K value and PFC value on Dry surface
1.10
: PFC (ASTM1136)
= 195/75R14（M/L Tiger Paw)=
1.05
: K value
(1~ 6; different vehicle)
1.00
0.95
1; 225/50R18
2; 215/65R16(M+S)
3; 175/65R14(AS)
4; 205/55R16
5; 215/45R17
6; 205/50R17
0.90
0.85
0.80
A
B
C
Proving ground
(K value)/(PFC value)
Fig. 1： Friction Coefficient between typical proving ground
1.3
Proving
Ground A
Proving
Ground B
Proving
Ground C
The surface friction difference
between proving ground is small.
(A-C: 6%)
K-value shows higher than PFC.
The difference depends on the
tyre performance.

1.2
1.1
1
0.9
0.8
1
2
3
4
5
6
Fig. 2： The Ratio of K-value to PFC value for passenger cars
(2)
Lateral Displacement Influenced by Surface Friction(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))
Vehicle
Simulation
software
A
CarSim
B
In-house soft
C
veDYNA
D
In-house soft
E
CarSim
F
ADAMS/Car
G
H
ADAMS
ADAMS
Wheel Base
FR P-car：A
SUV：L
FF P-car：B
SUV：M
FF P-car：C
SUV：N
FF P-car：D
SUV：O
FF P-car：E
SUV：P
FF P-car：F
SUV：Q
SUV：R
FF P-car：G
2730 [mm]
2720
2700
2900
2730
2880
2775
2850
2635
2670
2620
2620
2640
2440
Weight
1533 [kg]
1991
1570
1690
1520
2280
1659
2172
1375
1515
1400
1700
1896
958
Tyre
205/55R16
235/55R18
205/50R17
205/60R16
215/50R17
245/50R20
215/55R17
265/50R20
235/45R17
225/55R18
215/45R17
215/55R17
225/65R17
175/65R14
(3)
Lateral Displacement Influenced by Surface Friction(2)
2. An Example of time history data (Passenger Car)
[m]
6
0
Lateral Displacement
Steering Wheel Angle
[deg]
120
1.07
-120
-0.5
2
[m/s
0
0.5
1
1.5
2
2.5
3 [s]
SWA[deg]
m = 0.8
m = 0.9
m = 1.0
0
-6
-0.5
0
1
1.5
-2.0
]
Lateral Acceleration
0.5
2
2.5
3 [s]
[m]
μ= 0 .8
μ= 0 .9
μ= 1 .0
10
2.74
2.94
-3.5
0.9
1.2[s]
0
0
0.5
1
1.5
2
2.5
1.1
The influence of surface friction to the
lateral displacement is small, because
SWA[deg]
m = 0.8
m = 0.9
m = 1.0
-10-0.5
1
3 [s]
Fig 3： Time history data of passenger car
and
are canceled each other.
(4)
Lateral Displacement Influenced by Surface Friction(3)
3. All results
Lateral displacement [m]
3.5
P-car : A
P-car : B
P-car : C
P-car : D
P-car : E
P-car : F
P-car : G
3
SUV : L
SUV : M
SUV : N
SUV : O
SUV : P
SUV : Q
SUV : R
2.5
Ave. difference: 15cm
m@0.9 - m@0.8 = 18 cm
m@1.0 - m@0.9 = 13 cm
2
1.5
0.8
0.9
1
Friction coefficient (m)
Fig 4． The influence of the surface friction to the lateral displacement
(5)
= Reference : The testing error range (1)=
∫∫AYCG・dt・dt @ 1.07s [m]
2.5
2.4
2.3
2.2
2.1
22 [cm]
2.0
5
1
2
3
4
6
7
8
9
10
The tyre lot No.
Fig 5． An Example of the error range of driving test
by different lot number of tyres
= Reference : The testing error range (2) =
(6)
“Lateral Displacement” for SWAN > 5
• Least sensitivity to temperature (ΔT = 489 for 302)
• High S/N (11.0)
• 4 significant track differences
min(aycg_int_int_1p07_fs) for swan > 5
302: 3 Sig. Diff. by Track, M32: 1 Sig. Diff. by Track, S/N = 11.0
4
min(aycg_int_int_1p07_fs) for swan > 5
4
302
M32
3.8
302 R=-0.74; Slope = -1.21e-003; T = 489
M32 R=-0.34
3.8
3.6
3.6
3.4
20cm
18cm
3.4
3.2
3.2
3
3
2.8
2.8
18cm
2.6
AZ
CA
MI
Track
OH
SC
2.6
0
20
40
60
80
Final Ambient Temperature (deg F)
100
From NHTSA docket:No. 25801-9