Document ID: chunk:federal_register_of_legislation:F2021C00476:body:0:p39
Version: federal_register_of_legislation:F2021C00476
Segment Type: other
Provision Reference: 
Character Range: 108919–112062

time required for the pressure to rise from p2 to p1 in the energy storage device(s) without application of the brake control.

         2.1.2.  Conditions of measurement

         2.1.2.1. During the tests to determine the time t, the feed rate of the energy source shall be that obtained when the engine is running at the speed corresponding to its maximum power or at the speed allowed by the over-speed governor.

         2.1.2.2. During the test to determine the time t, energy storage device(s) for auxiliary equipment shall not be isolated other than automatically.

         2.1.3.  Interpretation of results

         2.1.3.1. In the case of all vehicles, the time t shall not exceed 20 seconds.

         3.  CHARACTERISTICS OF WARNING DEVICES

           With the engine stationary and commencing at a pressure that may be specified by the manufacturer but does not exceed the cut-in pressure, the warning device shall not operate following two full-stroke actuations of the service brake control.

Annex 5

DISTRIBUTION OF BRAKING AMONG THE AXLES OF VEHICLES

              1.  GENERAL

           Vehicles which are not equipped with an anti-lock system as defined in Annex 6 to this Regulation shall meet all the requirements of this annex.  If a special device is used, this must operate automatically.

              2.  SYMBOLS

                             i = axle index (i = 1, front axle;
    i = 2, rear axle)

                             Pi = normal reaction of road surface on axle i under static conditions

                             Ni = normal reaction of road surface on axle i under braking

                  Ti = force exerted by the brakes on axle i under normal braking conditions on the road

                             fi = Ti/Ni , adhesion utilized by axle i [10]/

                             J = deceleration of the vehicle

                             g = acceleration due to gravity : g = 9.81 m/s2

                             z = braking rate of vehicle = J/g

                             P = mass of vehicle

                  h = height of centre of gravity specified by the manufacturer and agreed by the Technical Services conducting the approval test

                             E = wheelbase

                             k = theoretical coefficient of adhesion between tyre and road

              3.  REQUIREMENTS

         3.1.(A)  For all states of load of the vehicle, the adhesion utilization curve of the rear axle shall not be situated above that for the front axle: [11]/
              for all braking rates between 0.15 and 0.8:

              3.1.(B)  For k values between 0.2 and 0.8: 2/
              z  0.1 + 0.7 (k - 0.2) (see diagram 1 of this annex)

         3.2.  In order to verify the requirements of paragraph 3.1. of this annex, the manufacturer shall provide the adhesion utilization curves for the front and rear axles calculated by the formulae:

              The curves shall be plotted for both the following load conditions:

              3.2.1.  unladen, in running order with the driver on board;

         3.2.2.  laden; where provision is made