Document ID: chunk:federal_register_of_legislation:F2010C00150:front:0:p31
Version: federal_register_of_legislation:F2010C00150
Segment Type: other
Provision Reference: 
Character Range: 84143–86887

lower deceleration rate than the lockup of both rear wheels when tested on road surfaces on which wheel lockup occurs at braking rates between 0.15 and 0.8m/ s2.

         (b) A simultaneous lockup of the front and rear wheels refers to the condition when the time interval between the lockup of the last (second) wheel on the rear axle and the last (second) wheel on the front axle is < 0.1 seconds for vehicle speeds > 30km/h.

2. VEHICLE CONDITIONS

(a) Vehicle load : Laden and unladen

(b) Transmission position : Engine disconnected

3. TEST CONDITIONS AND PROCEDURES

         (a) Initial brake temperature: Between 65 degrees C and 100 degrees C average on the hottest axle.

         (b) Test speed : 65km/h for a braking rate < 0.50 ; 100km/h for a braking rate > 0.50 .

(c) Pedal force :

         (1) Pedal force is applied and controlled by a skilled driver or by a mechanical brake pedal actuator.

         (2) Pedal force is increased at a linear rate such that the first axle lockup occurs no less than one-half (0.5) second and no more than one and one-half (1.5) seconds after the initial application of the pedal.

         (3) The pedal is released when the second axle locks, or when the pedal force reaches 1 kN, or 0.1 seconds after the first lockup, whichever occurs first.

         (d) Wheel lockup  : Only wheel lockups  above  a  vehicle speed of 15km/h are considered.

         (e) Test surface : This test is conducted on road test surfaces on which wheel lockup occurs at braking rates between 0.15 and 0.8m/s2

         (f) Data to be recorded : The following information must be automatically recorded in phase continuously throughout each test run such that values of the variables can be cross referenced in real time:

(1) vehicle speed ;

         (2) Instantaneous vehicle braking rate (e.g. by differentiation of vehicle speed);

(3) Brake pedal force (or hydraulic line pressure);

(4) Angular velocity at each wheel.

         (g) Each test run shall be repeated once to confirm the wheel lockup sequence: if one of these two results indicates a failure to comply, then a third test run under the same conditions will be decisive.

4. PERFORMANCE REQUIREMENTS

         (a) Both rear wheels shall not reach a locked condition prior to both front wheels being locked - at vehicle braking rates between 0.15 and 0.8m/s2.

         (b) If, when tested to the procedure specified above, and at vehicle braking rates between 0.15 and 0.8m/s2 the vehicle meets one of the following criteria, then it passes this wheel lockup sequence requirement:

(1) No wheels lock;

         (2) Both wheels on the front axle and one or no wheels on the rear axle lock;

(3) Both axles simultaneously lock.

         (c)