In order to determine the CO₂ reductions that can be attributed to the use of LEDs in the low beam headlamps, the high beam headlamps, and the licence plate lamps fitted to M1 vehicles the following are to be established:

1. (a)

   the electric power consumption of the LED lights used in the lighting functions in question;

2. (b)

   the savings in electric power consumption compared to the base line technology, i.e. halogen lights;

3. (c)

   the reduction in CO₂ emissions due to the savings in the electric power consumption.

The electric power consumption of the LEDs for each of the lighting functions concerned is to be determined as the multiplication of the battery voltage and the electric current of each lighting unit with the number of lights of each lighting unit, according to the formula:

$\mathrm{PLED\; =\; U\; \times \; I\; \times \; n}$;

PLED

electric power consumption of an LED lighting function (W);

U

battery voltage (V) This value can be measured with a multimeter;

I

electric current (A). This value can be measured with a multimeter;

n

number of lights in function.

The measurement of the power consumption of the LEDs may be done separate from the NEDC hot test (see point 4 of this Annex).

The savings in electric power consumption due to the LEDs are to be determined by comparing the electric power consumption of the baseline technology with that of the LEDs for each of the relevant lighting functions.

The total savings resulting from the comparison are to be multiplied by a usage factor representing the time during which the LEDs are fully activated.

The values specified in the table are to be applied for the electric power consumption of the base line technology and for the usage factors.

In order to quantify the impact of the electric power consumption on the CO₂ emissions the vehicle is to be tested on a chassis dynamometer by running a hot start NEDC test as specified in Annex 4a to Regulation No 83 of the Economic Commission for Europe of the United Nations (UN/ECE) — Uniform provisions concerning the approval of vehicles with regard to the emission of pollutants according to engine fuel requirements8.

In order to ensure repeatability of the measurement, the power of the additional electrical load must be significantly higher than the potential electrical power saving of the LEDs (the saving is less than 40 W). An additional load causing an extra electrical power production of the alternator of ~750 W is to be therefore selected.

In total 10 hot start NEDC tests are to be performed of which five with and five without the additional load of ~750 Watt. In order to minimise the variability of the test results, the oil temperature, ambient temperature, and the time between the experiments are to be monitored and kept constant at the start of the test.

For these variables and for the road load setting the following specifications are to be followed:

• the road load setting of the chassis dynamometer is to be determined according to the procedure for the calibration of the dynamometer as defined in Annex 7 to Regulation No 83 (UN/ECE);

• the engine is to be warmed up at the start of the test, i.e. the oil temperature shall be 92 °C < T < 96 °C;

• the ambient temperature is to be 22,0 °C < T < 23,8 °C;

• the time between the tests is not to exceed 45 minutes.

The following measurements are to be performed:

• the electric output of the alternator measured with the additional electric load of ~750 W (5 tests) (potentiometer) and without the additional load (5 tests);

• CO₂ emissions.

The difference between the average CO₂ emissions resulting from the ten tests performed in accordance with point 4 is to be multiplied with the average electric power savings determined in accordance with point 3 divided by the difference between the average electric power consumption resulting from the two tests performed with and without the additional electric load, i.e.:

CiCO2 = MiC – MiNC × ΔPMPiC- – PiNC-

C_iCO2

CO₂ saving of the LED lights (g/km)

M_iC

CO₂ mass emissions with additional electric load (g/km)

M_iNC

CO₂ mass emissions without additional electric load (g/km)

ΔΡ_M

average electrical power saving by using LED (W)

P_iC

average electrical power consumption with additional consumer (W)

P_iNC

average electrical power consumption without additional consumer (W)

The statistical significance of the measured effects is to be determined by calculating the standard deviation of the measured CO₂ values (with and without the additional load) and by comparing the difference of the measured CO₂ values (with and without the additional load) with the standard deviation. The difference of the measured CO₂ values is to be more than 3 times the standard deviation.