Document ID: chunk:federal_register_of_legislation:F2022C00213:reg:18:p5
Version: federal_register_of_legislation:F2022C00213
Segment Type: reg
Provision Reference: reg 18 (pt 5/6)
Character Range: 151722–154842

temperature in an appropriate manner.

         5.  SPECIFIED SPEED V

           The specified speed is required for determining the running resistance at the reference speed from the running resistance curve.  To determine the running resistance as a function of vehicle speed in the vicinity of the reference speed Vo, running resistances shall be measured at the specified speed V.  At least four to five points indicating the specified speeds, along with the reference speeds, are desired to be measured.

           Table 1 shows the specified speeds in accordance with the category of the vehicle.  The asterisk * indicates the reference speed in the table.

         Table 1

Category                                    Specified speeds (km/h)
V max.
> 130                                       120**/                   100  80*  60  40  20
130 – 100                                   90                       80*  60   40  20  -
100 – 70                                    60                       50*  40   30  20  -
< 70                                        50**                     40*  30   20  -   -
**/ if it could be reached by the vehicle.

         6.  ENERGY VARIATION DURING COAST-DOWN

         6.1.  Total road load power determination

         6.1.1. Measurement equipment and accuracy

           The margin of measurement error shall be less than 0.1 second for time and less than ± 0.5 km/h for speed.

         6.1.2. Test procedure

         6.1.2.1. Accelerate the vehicle to a speed of 5 km/h greater than the speed at which test measurement begins.

         6.1.2.2. Put the gearbox to neutral, or disconnect the power supply.

         6.1.2.3. Measure the time t1 taken by the vehicle to decelerate from:

           V2 = V + Δ Vkm/h  to  V1 = V - Δ Vkm/h

           where:
            Δ V < 5 km/h for nominal speed < 50 km/h
            Δ V < 10 km/h for nominal speed > 50 km/h

         6.1.2.4. Carry out the same test in the opposite direction, measuring time t2.

         6.1.2.5. Take the average T1 of the two times t1 and t2.

         6.1.2.6. Repeat these tests until the statistical accuracy (p) of the average

           is equal to or less than 4 per cent (p < 4 per cent).

           The statistical accuracy (p) is defined by:

          where:
            T is the coefficient given by the table below;
            s is the standard deviation:
            n is the number of tests

n     4     5     6     7     8     9     10
t     3.2   2.8   2.6   2.5   2.4   2.3   2.3
t/√n  1.6.  1.25  1.06  0.94  0.85  0.77  0.73

         6.1.2.7. Calculation of the running resistance force

          The running resistance force F at the specified speed V is calculated as follows:

 Where:
            MHP is the test mass.
                    Mr is the equivalent inertia mass of all the wheels and vehicle portions rotating with the wheels during coast down on the road.  Mr should be measured or calculated by an appropriate manner.
         6.1.2.8. The running resistance determined on the track shall be corrected to the reference ambient conditions as