Division 5 MEASUREMENTS AND DETERMINATION OF THE EFFICIENCY

United Kingdom

The efficiency of the 12 V efficient alternator shall be determined in accordance with ISO 8854:2012^f1, with the exception of the elements specified in the present paragraph.

The measurements shall be conducted at different operating points i, as defined in Table 1. The alternator current intensity is defined as half of the rated current for all operating points. For each speed the voltage and the output current of the alternator are to be kept constant, the voltage at 14,3 V.

Table 1

Operating pointi	Holding time[s]	Rotational frequencyn_i [min^-1]	Frequencyh_i
1	1 200	1 800	0,25
2	1 200	3 000	0,40
3	600	6 000	0,25
4	300	10 000	0,10

The efficiency shall be calculated in accordance with Formula 1.

All efficiency measurements shall be performed consecutively at least five (5) times. The average of the measurements at each operating point ( ) has to be calculated.

The efficiency of the eco-innovative alternator (η_EI) shall be calculated in accordance with Formula 2

The efficient alternator leads to saved mechanical power under real-world conditions (ΔP_mRW) and type approval conditions (ΔP_mTA) as defined in Formula 3.

Formula 3

ΔP_m = ΔP_mRW - ΔP_mTA

where the saved mechanical power under real-world conditions (ΔP_mRW) is calculated in accordance with Formula 4 and the saved mechanical power under type-approval conditions (ΔP_mTA) in accordance with Formula 5.

Where:

P_RW

Power requirement under real-world conditions [W], which is 750W

P_TA

Power requirement under type-approval conditions [W], which is 350W

η_B

Efficiency of the baseline alternator [%], which is 67%

Annotations

Footnotes

f1: ISO 8854:2012 Road vehicles – Alternators with regulators – Test methods and general requirements Reference number ISO 8854:2012, published on 1 June 2012.