Document ID: chunk:federal_register_of_legislation:F2021C01192:body:0:p42
Version: federal_register_of_legislation:F2021C01192
Segment Type: other
Provision Reference: 
Character Range: 112042–114905

a five-point, on-centre moving average for each data channel.
(b) For each brake application prescribed in paragraph 3.(e) above, determine the slope (brake factor) and pressure axis intercept (brake hold-off pressure) of the linear least squares equation best describing the measured torque output at each braked wheel as a function of measured line pressure applied at the same wheel. Only torque output values obtained from data collected when the vehicle deceleration is within the range of 0.15 g to 0.80 g are used in the regression analysis.
(c) Average the results of paragraph (b) above to calculate the average brake factor and brake hold-off pressure for all brake applications for the front axle.
(d) Average the results of paragraph (b) above to calculate the average brake factor and brake hold-off pressure for all brake applications for the rear axle.
(e) Using the relationship between front and rear brake line pressure determined in paragraph 3.(i) above and the dynamic tyre rolling radius, calculate the braking force at each axle as a function of front brake line pressure.

(f) Calculate the braking rate of the vehicle as a function of the front brake line pressure using the following equation:

                              Where
                            z = braking rate at a given front brake line pressure
                            T1, T2 = braking forces at the front and rear axles respectively, corresponding to the same front brake line pressure
                            P = vehicle mass

(g) Calculate the adhesion utilized at each axle as a function of braking rate using the following formulae:

The symbols are defined in paragraph 2. of this annex.
(h) Plot f1 and f2 as a function of z, for both laden and unladen load conditions. These are the adhesion utilization curves for the vehicle, which shall satisfy the requirements in paragraph 5.2.(a)(ii) of this annex (or, in the case of Conformity of Production checks, these curves shall satisfy the requirements in paragraph 6.2. of this annex).
Annex 6
  Test requirements for vehicles fitted with anti-lock systems
1.   General
1.1.  This annex defines the required braking performance for road vehicles fitted with anti-lock systems.
1.2.  The anti-lock systems known at present comprise a sensor or sensors, a controller or controllers and a modulator or modulators. Any device of a different design which may be introduced in the future, or where an anti-lock braking function is integrated into another system, shall be deemed to be an anti-lock braking system within the meaning of this annex and Annex 5 to this Regulation, if it provides performance equal to that prescribed by this annex.
2.   Definitions
2.1.  An "anti-lock system" is a part of a service braking system which automatically controls the degree of slip, in the direction of rotation of