Division 8.3 Determination of the downscaling factor

The downscaling factor f_dsc, is a function of the ratio r_max between the maximum required power of the cycle phases where the downscaling is to be applied and the rated power of the vehicle, P_rated.

The maximum required power P_req,max,i (in kW) is related to a specific time i and the corresponding vehicle speed v_i in the cycle trace and is calculated using the following equation:

where:

The cycle time i at which maximum power or power values close to maximum power is required is second 764 for the Class 1 cycle, second 1 574 for the Class 2 cycle and second 1 566 for the Class 3 cycle.

The corresponding vehicle speed values, v_i, and acceleration values, a_i, are as follows:

• v_i = 61,4 km/h, a_i = 0,22 m/s² for Class 1,

• v_i = 109,9 km/h, a_i = 0,36 m/s² for Class 2,

• v_i = 111,9 km/h, a_i = 0,50 m/s² for Class 3.

r_max shall be calculated using the following equation:

The downscaling factor, f_dsc, shall be calculated using the following equations:

if $r_{\max }<r_0$, then $f_{\mathrm{dsc}}=0$

and no downscaling shall be applied.

If $r_{\max }\ge r_0$, then $f_{\mathrm{dsc}}=a_1\times r_{\max }+b_1$

The calculation parameter/coefficients, r₀, a₁ and b₁, are as follows:

• Class 1 r₀ = 0,978, a₁ = 0,680, b₁ = – 0,665

• Class 2 r₀ = 0,866, a₁ = 0,606, b₁ = – 0,525.

• Class 3 r₀ = 0,867, a₁ = 0,588 b₁ = – 0,510.

The resulting f_dsc is mathematically rounded to 3 places of decimal and is applied only if it exceeds 0,010.

The following data shall be included in all relevant test reports:

1. (a)

   f_dsc;

2. (b)

   v_max;

3. (c)

   distance driven, m.

The distance shall be calculated as the sum of v_i in km/h divided by 3,6 over the whole cycle trace.