ANNEX

Methodology for determining the reduction in CO2 emissions due to the use of the Valeo Efficient Generation Alternator in an M1 vehicle

1. Introduction

In order to determine the CO2 reductions that can be attributed to the use of the Valeo EG Alternator in an M1 vehicle, it is necessary to establish the following:

2. Testing procedure

The efficiency of the alternator must be determined by doing measurements at different speeds: 1 800, 3 000, 6 000, 10 000 revolutions per minute. At each speed the alternator is charged at 50 % of the maximum load. For calculating the efficiency, a time distribution is to be 25 %, 40 %, 25 %, 10 % for respectively 1 800, 3 000, 6 000, 10 000 revolutions per minute (see the VDA approach as described in point 5.1.2 in Annex I to the Technical Guidelines).

This leads to the following formula (1):

With:

The set-up of the test bench and the testing procedure is to fulfil the precision requirements specified in ISO 8854:2012 (1).

3. Test bench

The test bench is to be a ‘榙irect drive‘�alternator test bench. The alternator is to be directly linked to the torque meter and to the shaft of the drive train. The alternator is to be loaded with a battery and an electronic load. See the test bench configuration in figure 1.

Figure 1

The test bench configuration

In figure 1 an overview of the test bench configuration is given. The alternator transfers the mechanical power of the brushless motor into electrical power. The brushless motor generates an amount of power which is defined by the torque (Nm) and by the rotational speed (rad.s‘�). The torque and the speed are to be measured by the torque meter.

The alternator produces power to overcome the load which is connected to the alternator. This amount of power is equal to the alternator voltage (V) times the alternator current (I).

The efficiency of the alternator is to be defined as the electric power (output of the alternator) divided by the mechanical power (output of the torquemeter).

Where:

4. Measuring the torque and calculating the efficiency of the alternator

The tests are to be carried out in accordance with the ISO 8854:2012.

The load is to be installed at 50 % of the current which is guaranteed by the alternator at 25 掳C and a rotor speed of 6 000 rpm, e.g. if the alternator is a 180 A class alternator (at 25 掳C and 6 000 rpm), the load is installed at 90 A.

For each speed the voltage and the output current of the alternator are to be kept constant, the voltage at 14,3 V and the current for a 180 A-alternator at 90 A, i.e. for each speed the torque is to be measured by means of the test bench (see figure 1) and the efficiency is to be calculated by means of formula (2).

This test is to provide the efficiencies of the alternator at 4 different speeds in revolutions per minute (rpm):

The average efficiency of the alternator is to be calculated by means of formula (1).

5. Standard deviation of the arithmetic mean value of the efficiency of the alternator

Statistical errors in the outcomes of the testing methodology caused by the measurements are to be quantified. The format of the error value is to be a standard deviation being equivalent to a two-sided confidence interval of 84 % (see formula (3)).

Where:

All measurements are to be performed consecutively at least five (5) times. For each speed the standard deviation is calculated.

The standard deviation of the efficiency value of the alternator (螖畏螒) is calculated by the following formula:

Where the values 0,25, 0,40, 0,25, and 0,1 are the same weighting values as in formula (2) and S1 800, S3 000, S6 000, and S10 000 are the standard deviations calculated with formula (3).

6. Error in the CO2 savings due to the standard deviation (propagation law)

The standard deviation of the efficiency value of the alternator (螖畏螒), leads to an error in the CO2 savings. This error is to be calculated by means of the following formula (2):

Where:

7. Calculation of the accountable share of the mechanical power saving

The high efficient alternator leads to the saved mechanical power which is to be calculated in two steps. In the first step the saved mechanical power is to be calculated under ‘榬eal world‘�conditions. The second step is to calculate the saved mechanical power under type approval conditions. Subtracting these 2 mechanical power savings is to result in the accountable share of the saved mechanical power.

The saved mechanical power under ‘榬eal world‘�conditions is to be calculated with formula (6).

Where:

The saved mechanical power under type-approval conditions is to be calculated with formula (7).

Where:

The accountable share of saved mechanical power is calculated with formula (8).

Where:

8. Formula to calculate the CO2 savings

The CO2 savings are to be calculated with the following formula:

Where:

For the Willans‘�factors the data in table 1 is to be used:

Table 1

Willans‘�factors

For the conversion factors the data in table 2 is to be used:

Table 2

Conversion factors

The mean driving speed of the NEDC is: v = 33,58 km/h

9. Statistical Significance

It has to be demonstrated for each type, variant and version of a vehicle fitted with the Valeo EG Alternator that the error in the CO2 savings calculated with Formula 5 is not greater than the difference between the total CO2 savings and the minimum savings threshold specified in Article 9(1) of Implementing Regulation (EU) No 725/2011 (see Formula (7)).

Where:

10. The high efficient alternator to be implemented in vehicles

For determining the CO2 savings to be certified due to the use of the Valeo EG Alternator by the type approval authority in accordance with Article 12 of Implementing Regulation (EU) No 725/2011, the manufacturer of the M1 vehicle in which the alternator is fitted has to designate in accordance with Article 5 of that Regulation, an eco-innovation vehicle fitted with the Valeo (EG) Alternator and either of the following baseline vehicles:

The type approval authority is to certify the CO2 savings based on measurements of the base vehicle and eco-innovation vehicle in accordance with Article 8(1) and the second subparagraph of Article 8(2) of Implementing Regulation (EU) No 725/2011 using the test methodology set out in this Annex. Where the CO2 emission savings are below the threshold specified in Article 9(1), the second subparagraph of Article 11(2) of Implementing Regulation (EU) No 725/2011 shall apply.

11. Eco-innovation code to be entered into type approval documentation

For the purposes of determining the general eco-innovation code to be used in the relevant type approval documents in accordance with Annexes I, VIII and IX to Directive 2007/46/EC, the individual code to be used for the innovative technology approved through this Decision shall be ‘�‘�

E.g. the code of the eco-innovation in the case of eco-innovation savings certified by the German type approval authority shall be ‘榚1 2‘�

(1) ISO 8854. Road vehicles ‘�Alternators with regulators ‘�Test methods and general requirements. Reference number ISO 8854:2012(E).

(2) This formula (5) can be derived from the error propagation law which is explained in the Technical Guidelines (par. 4.2.1).