QC/T 480-1999Limits and evaluation method for handling and stability of automobiles (English PDF)

2.1

This test evaluates and scores according to three indicators: lateral acceleration a n at the neutral turning point, understeer degree U and roll degree of trunk KPhi.

2.2

See Table 1 for the lower limits of a n , U and KPhi: an60 , U 60 and KPhi60 as well as the upper limits: a n100 , U 100 and K Phi100.

NOTE:

1) It is used for the automobiles of which the maximum speed is greater than 160km/h.

2) It is used for the passenger cars of which the maximum total mass is greater than 9t.

Criterion thresholds and evaluation of controllability and stability for automobiles […]

2.5

The roll degree of trunk K Phi is calculated according to the average slope

(divide the ordinate value by the abscissa value) at the position where the lateral acceleration is 2ms/

2 on the curve of relationship between the roll angle of trunk and the lateral acceleration. The evaluation score is calculated according to formula (3):

Where,

N Phi - The evaluation score of the trunk roll degree;

KPhi60 - The lower limit of the trunk roll degree, (°)/(m/s

2

);

K Phi100 - The upper limit of the trunk roll degree, (°)/(m/s

2

);

KPhi - The test value of the trunk roll degree, (°)/(m/s

2

).

2.5.1

When N Phi is greater than 100, score as 100.

2.6

The comprehensive evaluation score of steady-state rotation test is calculated according to formula (4):

Where,

N w - The comprehensive evaluation score of steady-state rotation test.

3.1

This test is evaluated and scored according to two indicators: the absolute value of residual yaw rate deltar when turning wheel (steering wheel) is released for 3s and the total variance of yaw rate Er .

3.4.1

When N E is greater than 100, score as 100.

3.5

Comprehensive evaluation score of cornering with steer release

performance test

3.5.1

For the automobiles that can only conduct the low-speed cornering test, it shall be evaluated and scored according to Ndeltar and N E, according to formula (7):

Where,

N H - The comprehensive evaluation score of cornering with steer release performance test.

3.5.2

For the automobiles that conduct low-speed and high-speed cornering tests, it shall be evaluated and scored according to four indicators: Ndeltar and N E of the low-speed cornering as well as N' deltar and N' E of the high-speed cornering, according to formula (8):

Where,

N' deltar - The evaluation score of the absolute value of residual yaw rate in high- […]

4.3.1 When N F

s is greater than 100, score as 100.

4.4

The evaluation score of the maximum steering force of steering wheel Fm is calculated according to formula (10):

Where,

N F m

- The evaluation score of the maximum steering force of steering wheel;

F m60 - The lower limit of the maximum steering force of steering wheel, N;

Fm100 - The upper limit of the maximum steering force of steering wheel, N;

Fm - The test value of the maximum steering force of steering wheel, N.

4.4.1 When N F

m is greater than 100, score as 100.

4.5

The comprehensive evaluation score of steering portability test is calculated according to formula (11):

Where,

N Q - The comprehensive evaluation score of steering portability;

- The weighting factor related to the maximum total mass of the vehicle, , (in t).

5 Steering transient response test (steering wheel angle step input) 5.1 This test is evaluated and scored according to the vehicle yaw rate response time T, when the lateral acceleration is 2m/s

2

.

6.4.3

When N D is greater than 100, score as 100.

6.5

The evaluation score of phase lag angle alpha is calculated according to formula

(16):

Where,

- The evaluation score of phase lag angle;

alpha 60 - The lower limit of phase lag angle, (°);

alpha 100 - The upper limit of phase lag angle, (°);

alpha - The test value of phase lag angle at the corresponding frequency (see the remark of Table 5), (°).

6.5.1

When is greater than 100, score as 100.

7.3.1

When Nr is greater than 100, score as 100.

7.4

The evaluation score of average steering wheel angle peak theta is calculated

according to formula (19):

Where,

N theta - The evaluation score of average steering wheel angle peak;

theta 60 - The lower limit of average steering wheel angle peak, (°);

theta 100 - The upper limit of average steering wheel angle peak, (°);

theta - The test value of average steering wheel angle peak at the base speed, (°).

7.4.1

When N theta is greater than 100, score as 100.

7.5

For the automobiles that fail to achieve the base speed, the evaluation scores of Nr and N theta shall be calculated according to formula (20):

Where,

V a - Pylon course slalom speed that is actually achieved, km/h;

V n - Base speed specified in Table 6, km/h.

7.6

The comprehensive evaluation score of pylon course slalom test is calculated according to formula (21):