Symbols and definitions. Table: Symbols and definitions Symbol Notes E wheelbase ε the adhesion utilized of the vehicle: quotient of the maximum braking rate with the anti-lock system operative (zAL) and the coefficient of adhesion (k) εi the ε - value measured on axle i (in the case of a motor vehicle with a category 3 anti-lock system) εH the ε - value on the high-adhesion surface εL the ε - value on the low-adhesion surface F force ( N ) Fdyn normal reaction of road surface under dynamic conditions with the anti-lock system operative Fidyn Fdyn on axle i in case of power-driven vehicles Fi normal reaction of road surface on axle i under static conditions FM total normal static reaction of road surface on all wheels of power-driven vehicle FMnd1 total normal static reaction of road surface on the unbraked and non-driven axles of the power-driven vehicle FMd1 total normal static reaction of road surface on the unbraked and driven axles of the power-driven vehicle FWM1 0.01 FMnd + 0.015 FMd g acceleration due to gravity (9.81 m/s2) h height of centre of gravity specified by the manufacturer and agreed by the Technical Service conducting the approval test k coefficient of adhesion between tyre and road kf k - factor of one front axle kH k - value determined on the high-adhesion surface ki k - value determined on axle i for a vehicle with a category 3 anti-lock system 1 FMnd and FMd in case of two-axled motor vehicles: these symbols may be simplified to corresponding Fi - symbols. Table: Symbols and definitions Symbol Notes kL k - value determined on the low-adhesion surface klock value xx xxhesion for 100 per cent slip kM k - factor of the power-driven vehicle kpeak maximum value of the curve "adhesion versus slip" kr k - factor of one rear axle P mass of individual vehicle (kg) R ratio of kpeak to klock t timx xxxerval (s) tm mean value of t tmin minimum value of t z braking rate zAL braking rate z of the vehicle with the anti-lock system operative zm mean braking rate zmax maximum value of z zMALS zAL of the power-driven vehicle on a "split surface" Annex 6 Appendix 2 Utilization of adhesion
Symbols and definitions. Note: The reference brake symbols shall have the suffix "e" P = normal reaction of road surface on the axle under static conditions C = camshaft input torque Cmax = maximum technically permissible camshaft input torque Co = threshold camshaft input torque, i.e., minimum camshaft torque necessary to produce a measurable brake torque R = tyre rolling radius (dynamic) T = brake force at tyre/road interface M = brake torque = T.R z = braking rate = T/P or M/RP s = actuator stroke (working stroke plus free stroke) sp = effective stroke - the stroke at which the output thrust is 90 per cent of the average thrust (ThA) ThA = average thrust - the average thrust is determined by integrating the values between one third and two thirds of the total stroke (smax) l = lever length r = radius of brake drums p = brake actuation pressure
