# Commission Regulation (EU) 2017/1151 of 1 June 2017 supplementing Regulation (EC) No 715/2007 of the European Parliament and of the Council on type-approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) and on access to vehicle repair and maintenance information, amending Directive 2007/46/EC of the European Parliament and of the Council, Commission Regulation (EC) No 692/2008 and Commission Regulation (EU) No 1230/2012 and repealing Commission Regulation (EC) No 692/2008 (Text with EEA relevance), Division 8.3: Determination of the downscaling factor


The downscaling factor fdsc, is a function of the ratio rmax between the maximum required power of the cycle phases where the downscaling is to be applied and the rated power of the vehicle, Prated.
The maximum required power Preq,max,i (in kW) is related to a specific time i and the corresponding vehicle speed vi in the cycle trace and is calculated using the following equation:
Preq,max,i=f0× vi+f1× v2i+f2× v3i+1,03× TM× vi× ai3600where:
f0, f1, f2are the applicable road load coefficients, N, N/(km/h), and N/(km/h)2 respectively;
TMis the applicable test mass, kg;
viis the speed at time i, km/h;
aiis the acceleration at time i, km/h2.
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, vi, and acceleration values, ai, are as follows:
vi = 61,4 km/h, ai = 0,22 m/s2 for Class 1,
vi = 109,9 km/h, ai = 0,36 m/s2 for Class 2,
vi = 111,9 km/h, ai = 0,50 m/s2 for Class 3.
rmax shall be calculated using the following equation:
rmax=Preq,max,iPratedThe downscaling factor, fdsc, shall be calculated using the following equations:
if rmax<r0, then fdsc=0
and no downscaling shall be applied.
If rmax≥r0, then fdsc=a1× rmax+ b1
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 fdsc 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:
(a)fdsc;
(b)vmax;
(c)distance driven, m.
The distance shall be calculated as the sum of vi in km/h divided by 3,6 over the whole cycle trace.

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Source: https://www.legislation.gov.uk/eur/2017/1151/annex/Sub/1/division/division/8./division/8.3. (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-1151/annex-Sub/1/division/division-8./division-8.3.
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.