Commission Implementing Decision (EU) 2017/785 of 5 May 2017 on the approval of efficient 12 V motor-generators for use in conventional combustion engine powered passenger cars as an innovative technology for reducing CO2 emissions from passenger cars pursuant to Regulation (EC) No 443/2009 of the European Parliament and of the Council (Text with EEA relevance) (c. 785)

ANNEX U.K. METHODOLOGY TO DETERMINE THE CO₂ SAVINGS OF EFFICIENT 12 V MOTOR-GENERATORS FOR CONVENTIONAL COMBUSTION ENGINE POWERED M1 VEHICLES

3. Measurements and determination of the efficiency U.K.

The efficiency of the 12 V motor generator shall be determined in accordance with ISO 8854:2012, with the exception of the elements specified in this point.

Evidence shall be provided to the type approval authority that the speed ranges of the efficient 12 V motor generator are consistent with those set out in Table 1. The measurements shall be conducted at different operating points, as set out in Table 1. The efficient 12 V motor generator current intensity shall be defined as half of the rated current for all operating points. For each speed the voltage and the output current of the alternator shall be kept constant at 14,3 V.

Table 1

Operating points

Operating pointi	Holding time[s]	Rotational frequencyni[min– 1]	Frequencyhi
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 at each operating point shall be calculated in accordance with the following Formula 1:

Formula 1 U.K.

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

The efficiency of the motor generator (η_MG) shall be calculated in accordance with the following Formula 2:

Formula 2 U.K.

The motor generator leads to saved mechanical power under real-world conditions (ΔP_mRW) and type approval conditions (ΔP_mTA) as set out in Formula 3.

Formula 3 U.K.

Where the saved mechanical power under real-world conditions (ΔP_mRW) shall be calculated in accordance with Formula 4 and the saved mechanical power under type-approval conditions (ΔP_mTA) in accordance with the following Formula 5:

Formula 4 U.K.

Formula 5 U.K.

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 %